This again? I know!
Apologies to all who hoped I'd stop bothering them with this
patch set, but I ran afoul of the DRM tree rules by not
getting the userland patches properly reviewed prior to the
patches landing (I mistakenly was waiting for the patches to
land upstream before pushing the userland patches). Thus,
these were correctly reverted from the drm-misc-next tree.
My attempts to quickly fix the userland review issue didn't get
very far, as the revert brought additional eyes to the patchset,
and further interface changes were requested (comically, which
is the exact reason I was waiting to push the userland changes
:)
So like groundhog day, here we are again, with v14:
This patchset implements per-heap devices which can be opened
directly and then an ioctl is used to allocate a dmabuf from the
heap.
The interface is similar, but much simpler then IONs, only
providing an ALLOC ioctl (and a GET_FEATURES interface to help
with any future changes to the interface).
Also, I've provided relatively simple system and cma heaps.
I've booted and tested these patches with AOSP on the HiKey960
using the kernel tree here:
https://git.linaro.org/people/john.stultz/android-dev.git/log/?h=dev/dma-buf-heap
And the userspace changes here:
https://android-review.googlesource.com/c/device/linaro/hikey/+/909436
Compared to ION, this patchset is missing the system-contig,
carveout and chunk heaps, as I don't have a device that uses
those, so I'm unable to do much useful validation there.
Additionally we have no upstream users of chunk or carveout,
and the system-contig has been deprecated in the common/andoid-*
kernels, so this should be ok.
I've also removed the stats accounting, since any such
accounting should be implemented by dma-buf core or the heaps
themselves.
New in v14:
* Reworked ioctl handler to zero fill any difference in
structure size, similar to what the DRM core does, as
suggested by Dave Airlie
* Removed now unnecessary reserved bits in allocate_data
* Added get_features ioctl as suggested by Dave Airlie
* Removed pr_warn_once messages as requested by Dave
Airlie
* Fix missing argment to WARN() in dma_heap_buffer_destroy()
found and fixed by Dan Carpenter <[email protected]>
* Add check in fault hanlder that pgoff isn't larger then
pagecount, reported by Dan Carpenter
* Fix "redundant assignment to variable ret" issue reported
by Colin King and fixed by Andrew Davis
* Fix a missing return value in kselftest
* Add calls to test the GET_FEATURES ioctl in ksefltest
* Build fix reported by kernel test robot <[email protected]>
and fixed by Xiao Yang <[email protected]> for kselftest
* Minor kselftest Makefile cleanups
Many thanks again to the folks above who found and submitted
fixes to small issues while the patches were in -next! I've
folded them in to the patch set here.
The ioctl rework to avoid reserved fields, was mostly duplicated
from the DRM core, but it does add some complexity to the ioctl
handler so I'd appreciate extra review.
It felt substantial enough that I've removed the previous reviewed
by and acked-by tags, but please let me know if you'd like me to
re-add yours back.
Apologies again for my flub and the extra noise here!
I really appreciate everyone's patience with with me.
thanks
-john
Cc: Laura Abbott <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Pratik Patel <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Sudipto Paul <[email protected]>
Cc: Andrew F. Davis <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chenbo Feng <[email protected]>
Cc: Alistair Strachan <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Andrew F. Davis (1):
dma-buf: Add dma-buf heaps framework
John Stultz (4):
dma-buf: heaps: Add heap helpers
dma-buf: heaps: Add system heap to dmabuf heaps
dma-buf: heaps: Add CMA heap to dmabuf heaps
kselftests: Add dma-heap test
MAINTAINERS | 18 +
drivers/dma-buf/Kconfig | 11 +
drivers/dma-buf/Makefile | 2 +
drivers/dma-buf/dma-heap.c | 313 ++++++++++++++++++
drivers/dma-buf/heaps/Kconfig | 14 +
drivers/dma-buf/heaps/Makefile | 4 +
drivers/dma-buf/heaps/cma_heap.c | 178 ++++++++++
drivers/dma-buf/heaps/heap-helpers.c | 271 +++++++++++++++
drivers/dma-buf/heaps/heap-helpers.h | 55 +++
drivers/dma-buf/heaps/system_heap.c | 124 +++++++
include/linux/dma-heap.h | 59 ++++
include/uapi/linux/dma-heap.h | 77 +++++
tools/testing/selftests/dmabuf-heaps/Makefile | 6 +
.../selftests/dmabuf-heaps/dmabuf-heap.c | 255 ++++++++++++++
14 files changed, 1387 insertions(+)
create mode 100644 drivers/dma-buf/dma-heap.c
create mode 100644 drivers/dma-buf/heaps/Kconfig
create mode 100644 drivers/dma-buf/heaps/Makefile
create mode 100644 drivers/dma-buf/heaps/cma_heap.c
create mode 100644 drivers/dma-buf/heaps/heap-helpers.c
create mode 100644 drivers/dma-buf/heaps/heap-helpers.h
create mode 100644 drivers/dma-buf/heaps/system_heap.c
create mode 100644 include/linux/dma-heap.h
create mode 100644 include/uapi/linux/dma-heap.h
create mode 100644 tools/testing/selftests/dmabuf-heaps/Makefile
create mode 100644 tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
--
2.17.1
Add very trivial allocation and import test for dma-heaps,
utilizing the vgem driver as a test importer.
A good chunk of this code taken from:
tools/testing/selftests/android/ion/ionmap_test.c
Originally by Laura Abbott <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Pratik Patel <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Sudipto Paul <[email protected]>
Cc: Andrew F. Davis <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chenbo Feng <[email protected]>
Cc: Alistair Strachan <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Reviewed-by: Benjamin Gaignard <[email protected]>
Reviewed-by: Brian Starkey <[email protected]>
Acked-by: Laura Abbott <[email protected]>
Tested-by: Ayan Kumar Halder <[email protected]>
Signed-off-by: John Stultz <[email protected]>
---
v2:
* Switched to use reworked dma-heap apis
v3:
* Add simple mmap
* Utilize dma-buf testdev to test importing
v4:
* Rework to use vgem
* Pass in fd_flags to match interface changes
* Skip . and .. dirs
v6:
* Number of style/cleanups suggested by Brian
v7:
* Whitespace fixup for checkpatch
v8:
* More checkpatch whitespace fixups
v9:
* Better handling error returns out to main, suggested
by Brian Starkey
* Switch to using snprintf, suggested by Brian
v14:
* Fix a missing return value
* Add calls to test the GET_FEATURES ioctl
* Build fix reported by kernel test robot <[email protected]>
and fixed by Xiao Yang <[email protected]>
* Minor Makefile cleanups
---
tools/testing/selftests/dmabuf-heaps/Makefile | 6 +
.../selftests/dmabuf-heaps/dmabuf-heap.c | 255 ++++++++++++++++++
2 files changed, 261 insertions(+)
create mode 100644 tools/testing/selftests/dmabuf-heaps/Makefile
create mode 100644 tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
diff --git a/tools/testing/selftests/dmabuf-heaps/Makefile b/tools/testing/selftests/dmabuf-heaps/Makefile
new file mode 100644
index 000000000000..607c2acd2082
--- /dev/null
+++ b/tools/testing/selftests/dmabuf-heaps/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS += -static -O3 -Wl,-no-as-needed -Wall -I../../../../usr/include
+
+TEST_GEN_PROGS = dmabuf-heap
+
+include ../lib.mk
diff --git a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
new file mode 100644
index 000000000000..ec47901ef2e2
--- /dev/null
+++ b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+
+#include <linux/dma-buf.h>
+#include <drm/drm.h>
+
+#include "../../../../include/uapi/linux/dma-heap.h"
+
+#define DEVPATH "/dev/dma_heap"
+
+static int check_vgem(int fd)
+{
+ drm_version_t version = { 0 };
+ char name[5];
+ int ret;
+
+ version.name_len = 4;
+ version.name = name;
+
+ ret = ioctl(fd, DRM_IOCTL_VERSION, &version);
+ if (ret)
+ return 0;
+
+ return !strcmp(name, "vgem");
+}
+
+static int open_vgem(void)
+{
+ int i, fd;
+ const char *drmstr = "/dev/dri/card";
+
+ fd = -1;
+ for (i = 0; i < 16; i++) {
+ char name[80];
+
+ snprintf(name, 80, "%s%u", drmstr, i);
+
+ fd = open(name, O_RDWR);
+ if (fd < 0)
+ continue;
+
+ if (!check_vgem(fd)) {
+ close(fd);
+ fd = -1;
+ continue;
+ } else {
+ break;
+ }
+ }
+ return fd;
+}
+
+static int import_vgem_fd(int vgem_fd, int dma_buf_fd, uint32_t *handle)
+{
+ struct drm_prime_handle import_handle = {
+ .fd = dma_buf_fd,
+ .flags = 0,
+ .handle = 0,
+ };
+ int ret;
+
+ ret = ioctl(vgem_fd, DRM_IOCTL_PRIME_FD_TO_HANDLE, &import_handle);
+ if (ret == 0)
+ *handle = import_handle.handle;
+ return ret;
+}
+
+static void close_handle(int vgem_fd, uint32_t handle)
+{
+ struct drm_gem_close close = {
+ .handle = handle,
+ };
+
+ ioctl(vgem_fd, DRM_IOCTL_GEM_CLOSE, &close);
+}
+
+static int dmabuf_heap_open(char *name)
+{
+ int ret, fd;
+ char buf[256];
+
+ ret = snprintf(buf, 256, "%s/%s", DEVPATH, name);
+ if (ret < 0) {
+ printf("snprintf failed!\n");
+ return ret;
+ }
+
+ fd = open(buf, O_RDWR);
+ if (fd < 0)
+ printf("open %s failed!\n", buf);
+ return fd;
+}
+
+static int dmabuf_heap_get_features(int fd, unsigned long long *features)
+{
+ struct dma_heap_get_features_data data = {0};
+ int ret;
+
+ ret = ioctl(fd, DMA_HEAP_IOC_GET_FEATURES, &data);
+ if (ret < 0)
+ return ret;
+
+ *features = (int)data.features;
+ return ret;
+}
+
+static int dmabuf_heap_alloc(int fd, size_t len, unsigned int flags,
+ int *dmabuf_fd)
+{
+ struct dma_heap_allocation_data data = {
+ .len = len,
+ .fd_flags = O_RDWR | O_CLOEXEC,
+ .heap_flags = flags,
+ };
+ int ret;
+
+ if (!dmabuf_fd)
+ return -EINVAL;
+
+ ret = ioctl(fd, DMA_HEAP_IOC_ALLOC, &data);
+ if (ret < 0)
+ return ret;
+ *dmabuf_fd = (int)data.fd;
+ return ret;
+}
+
+static void dmabuf_sync(int fd, int start_stop)
+{
+ struct dma_buf_sync sync = {
+ .flags = start_stop | DMA_BUF_SYNC_RW,
+ };
+ int ret;
+
+ ret = ioctl(fd, DMA_BUF_IOCTL_SYNC, &sync);
+ if (ret)
+ printf("sync failed %d\n", errno);
+}
+
+#define ONE_MEG (1024 * 1024)
+
+static int do_test(char *heap_name)
+{
+ int heap_fd = -1, dmabuf_fd = -1, importer_fd = -1;
+ uint32_t handle = 0;
+ void *p = NULL;
+ unsigned long long features;
+ int ret;
+
+ printf("Testing heap: %s\n", heap_name);
+
+ heap_fd = dmabuf_heap_open(heap_name);
+ if (heap_fd < 0)
+ return -1;
+
+ dmabuf_heap_get_features(heap_fd, &features);
+ printf("Interface features: 0x%llx\n", features);
+
+ printf("Allocating 1 MEG\n");
+ ret = dmabuf_heap_alloc(heap_fd, ONE_MEG, 0, &dmabuf_fd);
+ if (ret) {
+ printf("Allocation Failed!\n");
+ ret = -1;
+ goto out;
+ }
+ /* mmap and write a simple pattern */
+ p = mmap(NULL,
+ ONE_MEG,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ dmabuf_fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ ret = -1;
+ goto out;
+ }
+ printf("mmap passed\n");
+
+ dmabuf_sync(dmabuf_fd, DMA_BUF_SYNC_START);
+ memset(p, 1, ONE_MEG / 2);
+ memset((char *)p + ONE_MEG / 2, 0, ONE_MEG / 2);
+ dmabuf_sync(dmabuf_fd, DMA_BUF_SYNC_END);
+
+ importer_fd = open_vgem();
+ if (importer_fd < 0) {
+ ret = importer_fd;
+ printf("Failed to open vgem\n");
+ goto out;
+ }
+
+ ret = import_vgem_fd(importer_fd, dmabuf_fd, &handle);
+ if (ret < 0) {
+ printf("Failed to import buffer\n");
+ goto out;
+ }
+ printf("import passed\n");
+
+ dmabuf_sync(dmabuf_fd, DMA_BUF_SYNC_START);
+ memset(p, 0xff, ONE_MEG);
+ dmabuf_sync(dmabuf_fd, DMA_BUF_SYNC_END);
+ printf("syncs passed\n");
+
+ close_handle(importer_fd, handle);
+ ret = 0;
+
+out:
+ if (p)
+ munmap(p, ONE_MEG);
+ if (importer_fd >= 0)
+ close(importer_fd);
+ if (dmabuf_fd >= 0)
+ close(dmabuf_fd);
+ if (heap_fd >= 0)
+ close(heap_fd);
+
+ return ret;
+}
+
+int main(void)
+{
+ DIR *d;
+ struct dirent *dir;
+ int ret = -1;
+
+ d = opendir(DEVPATH);
+ if (!d) {
+ printf("No %s directory?\n", DEVPATH);
+ return -1;
+ }
+
+ while ((dir = readdir(d)) != NULL) {
+ if (!strncmp(dir->d_name, ".", 2))
+ continue;
+ if (!strncmp(dir->d_name, "..", 3))
+ continue;
+
+ ret = do_test(dir->d_name);
+ if (ret)
+ break;
+ }
+ closedir(d);
+
+ return ret;
+}
--
2.17.1
This patch adds system heap to the dma-buf heaps framework.
This allows applications to get a page-allocator backed dma-buf
for non-contiguous memory.
This code is an evolution of the Android ION implementation, so
thanks to its original authors and maintainters:
Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
Cc: Laura Abbott <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Pratik Patel <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Sudipto Paul <[email protected]>
Cc: Andrew F. Davis <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chenbo Feng <[email protected]>
Cc: Alistair Strachan <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Reviewed-by: Benjamin Gaignard <[email protected]>
Reviewed-by: Brian Starkey <[email protected]>
Acked-by: Laura Abbott <[email protected]>
Tested-by: Ayan Kumar Halder <[email protected]>
Signed-off-by: John Stultz <[email protected]>
---
v2:
* Switch allocate to return dmabuf fd
* Simplify init code
* Checkpatch fixups
* Droped dead system-contig code
v3:
* Whitespace fixups from Benjamin
* Make sure we're zeroing the allocated pages (from Liam)
* Use PAGE_ALIGN() consistently (suggested by Brian)
* Fold in new registration style from Andrew
* Avoid needless dynamic allocation of sys_heap (suggested by
Christoph)
* Minor cleanups
* Folded in changes from Andrew to use simplified page list
from the heap helpers
v4:
* Optimization to allocate pages in chunks, similar to old
pagepool code
* Use fd_flags when creating dmabuf fd (Suggested by Benjamin)
v5:
* Back out large order page allocations (was leaking memory,
as the page array didn't properly track order size)
v6:
* Minor whitespace change suggested by Brian
* Remove unused variable
v7:
* Use newly lower-cased init_heap_helper_buffer helper
* Add system heap DOS avoidance suggested by Laura from ION code
* Use new dmabuf export helper
v8:
* Make struct dma_heap_ops consts (suggested by Christoph)
* Get rid of needless struct system_heap (suggested by Christoph)
* Condense dma_heap_buffer and heap_helper_buffer (suggested by
Christoph)
* Add forgotten include file to fix build issue on x86
v12:
* Minor tweaks to prep loading heap from module
v14:
* Fix "redundant assignment to variable ret" issue reported
by Colin King and fixed by Andrew Davis
---
drivers/dma-buf/Kconfig | 2 +
drivers/dma-buf/heaps/Kconfig | 6 ++
drivers/dma-buf/heaps/Makefile | 1 +
drivers/dma-buf/heaps/system_heap.c | 124 ++++++++++++++++++++++++++++
4 files changed, 133 insertions(+)
create mode 100644 drivers/dma-buf/heaps/Kconfig
create mode 100644 drivers/dma-buf/heaps/system_heap.c
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index bffa58fc3e6e..0613bb7770f5 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -53,4 +53,6 @@ menuconfig DMABUF_HEAPS
allows userspace to allocate dma-bufs that can be shared
between drivers.
+source "drivers/dma-buf/heaps/Kconfig"
+
endmenu
diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
new file mode 100644
index 000000000000..205052744169
--- /dev/null
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -0,0 +1,6 @@
+config DMABUF_HEAPS_SYSTEM
+ bool "DMA-BUF System Heap"
+ depends on DMABUF_HEAPS
+ help
+ Choose this option to enable the system dmabuf heap. The system heap
+ is backed by pages from the buddy allocator. If in doubt, say Y.
diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
index de49898112db..d1808eca2581 100644
--- a/drivers/dma-buf/heaps/Makefile
+++ b/drivers/dma-buf/heaps/Makefile
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0
obj-y += heap-helpers.o
+obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
new file mode 100644
index 000000000000..9a56393e40b4
--- /dev/null
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DMABUF System heap exporter
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2019 Linaro Ltd.
+ */
+
+#include <linux/dma-buf.h>
+#include <linux/dma-mapping.h>
+#include <linux/dma-heap.h>
+#include <linux/err.h>
+#include <linux/highmem.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <asm/page.h>
+
+#include "heap-helpers.h"
+
+struct dma_heap *sys_heap;
+
+static void system_heap_free(struct heap_helper_buffer *buffer)
+{
+ pgoff_t pg;
+
+ for (pg = 0; pg < buffer->pagecount; pg++)
+ __free_page(buffer->pages[pg]);
+ kfree(buffer->pages);
+ kfree(buffer);
+}
+
+static int system_heap_allocate(struct dma_heap *heap,
+ unsigned long len,
+ unsigned long fd_flags,
+ unsigned long heap_flags)
+{
+ struct heap_helper_buffer *helper_buffer;
+ struct dma_buf *dmabuf;
+ int ret = -ENOMEM;
+ pgoff_t pg;
+
+ helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
+ if (!helper_buffer)
+ return -ENOMEM;
+
+ init_heap_helper_buffer(helper_buffer, system_heap_free);
+ helper_buffer->flags = heap_flags;
+ helper_buffer->heap = heap;
+ helper_buffer->size = len;
+
+ helper_buffer->pagecount = len / PAGE_SIZE;
+ helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
+ sizeof(*helper_buffer->pages),
+ GFP_KERNEL);
+ if (!helper_buffer->pages) {
+ ret = -ENOMEM;
+ goto err0;
+ }
+
+ for (pg = 0; pg < helper_buffer->pagecount; pg++) {
+ /*
+ * Avoid trying to allocate memory if the process
+ * has been killed by by SIGKILL
+ */
+ if (fatal_signal_pending(current))
+ goto err1;
+
+ helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!helper_buffer->pages[pg])
+ goto err1;
+ }
+
+ /* create the dmabuf */
+ dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+ if (IS_ERR(dmabuf)) {
+ ret = PTR_ERR(dmabuf);
+ goto err1;
+ }
+
+ helper_buffer->dmabuf = dmabuf;
+
+ ret = dma_buf_fd(dmabuf, fd_flags);
+ if (ret < 0) {
+ dma_buf_put(dmabuf);
+ /* just return, as put will call release and that will free */
+ return ret;
+ }
+
+ return ret;
+
+err1:
+ while (pg > 0)
+ __free_page(helper_buffer->pages[--pg]);
+ kfree(helper_buffer->pages);
+err0:
+ kfree(helper_buffer);
+
+ return ret;
+}
+
+static const struct dma_heap_ops system_heap_ops = {
+ .allocate = system_heap_allocate,
+};
+
+static int system_heap_create(void)
+{
+ struct dma_heap_export_info exp_info;
+ int ret = 0;
+
+ exp_info.name = "system_heap";
+ exp_info.ops = &system_heap_ops;
+ exp_info.priv = NULL;
+
+ sys_heap = dma_heap_add(&exp_info);
+ if (IS_ERR(sys_heap))
+ ret = PTR_ERR(sys_heap);
+
+ return ret;
+}
+module_init(system_heap_create);
+MODULE_LICENSE("GPL v2");
--
2.17.1
Add generic helper dmabuf ops for dma heaps, so we can reduce
the amount of duplicative code for the exported dmabufs.
This code is an evolution of the Android ION implementation, so
thanks to its original authors and maintainters:
Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
Cc: Laura Abbott <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Pratik Patel <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Sudipto Paul <[email protected]>
Cc: Andrew F. Davis <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chenbo Feng <[email protected]>
Cc: Alistair Strachan <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Reviewed-by: Benjamin Gaignard <[email protected]>
Reviewed-by: Brian Starkey <[email protected]>
Acked-by: Laura Abbott <[email protected]>
Tested-by: Ayan Kumar Halder <[email protected]>
Signed-off-by: John Stultz <[email protected]>
---
v2:
* Removed cache management performance hack that I had
accidentally folded in.
* Removed stats code that was in helpers
* Lots of checkpatch cleanups
v3:
* Uninline INIT_HEAP_HELPER_BUFFER (suggested by Christoph)
* Switch to WARN on buffer destroy failure (suggested by Brian)
* buffer->kmap_cnt decrementing cleanup (suggested by Christoph)
* Extra buffer->vaddr checking in dma_heap_dma_buf_kmap
(suggested by Brian)
* Switch to_helper_buffer from macro to inline function
(suggested by Benjamin)
* Rename kmap->vmap (folded in from Andrew)
* Use vmap for vmapping - not begin_cpu_access (folded in from
Andrew)
* Drop kmap for now, as its optional (folded in from Andrew)
* Fold dma_heap_map_user into the single caller (foled in from
Andrew)
* Folded in patch from Andrew to track page list per heap not
sglist, which simplifies the tracking logic
v4:
* Moved dma-heap.h change out to previous patch
v6:
* Minor cleanups and typo fixes suggested by Brian
v7:
* Removed stray ;
* Make init_heap_helper_buffer lowercase, as suggested by Christoph
* Add dmabuf export helper to reduce boilerplate code
v8:
* Remove unused private_flags value
* Condense dma_heap_buffer and heap_helper_buffer (suggested by
Christoph)
* Fix indentation by using shorter argument names (suggested by
Christoph)
* Add flush_kernel_vmap_range/invalidate_kernel_vmap_range calls
(suggested by Christoph)
* Checkpatch whitespace fixups
v9:
* Minor cleanups suggested by Brian Starkey
v10:
* Fix missing vmalloc.h inclusion in heap helpers (found by
kbuild test robot <[email protected]>)
v12:
* Add symbol exports for heaps as modules
v13:
* Re-remove symbol exports, per discussion with Brian, as I'll
resubmit the change for review independently.
v14:
* Fix missing argment to WARN() in dma_heap_buffer_destroy()
found and fixed by Dan Carpenter <[email protected]>
* Add check in fault hanlder that pgoff isn't larger then
pagecount, reported by Dan Carpenter
---
drivers/dma-buf/Makefile | 1 +
drivers/dma-buf/heaps/Makefile | 2 +
drivers/dma-buf/heaps/heap-helpers.c | 271 +++++++++++++++++++++++++++
drivers/dma-buf/heaps/heap-helpers.h | 55 ++++++
4 files changed, 329 insertions(+)
create mode 100644 drivers/dma-buf/heaps/Makefile
create mode 100644 drivers/dma-buf/heaps/heap-helpers.c
create mode 100644 drivers/dma-buf/heaps/heap-helpers.h
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index caee5eb3d351..9c190026bfab 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -2,6 +2,7 @@
obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
dma-resv.o seqno-fence.o
obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
+obj-$(CONFIG_DMABUF_HEAPS) += heaps/
obj-$(CONFIG_SYNC_FILE) += sync_file.o
obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
obj-$(CONFIG_UDMABUF) += udmabuf.o
diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
new file mode 100644
index 000000000000..de49898112db
--- /dev/null
+++ b/drivers/dma-buf/heaps/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y += heap-helpers.o
diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c
new file mode 100644
index 000000000000..9f964ca3f59c
--- /dev/null
+++ b/drivers/dma-buf/heaps/heap-helpers.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/err.h>
+#include <linux/highmem.h>
+#include <linux/idr.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <uapi/linux/dma-heap.h>
+
+#include "heap-helpers.h"
+
+void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
+ void (*free)(struct heap_helper_buffer *))
+{
+ buffer->priv_virt = NULL;
+ mutex_init(&buffer->lock);
+ buffer->vmap_cnt = 0;
+ buffer->vaddr = NULL;
+ buffer->pagecount = 0;
+ buffer->pages = NULL;
+ INIT_LIST_HEAD(&buffer->attachments);
+ buffer->free = free;
+}
+
+struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
+ int fd_flags)
+{
+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+ exp_info.ops = &heap_helper_ops;
+ exp_info.size = buffer->size;
+ exp_info.flags = fd_flags;
+ exp_info.priv = buffer;
+
+ return dma_buf_export(&exp_info);
+}
+
+static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer)
+{
+ void *vaddr;
+
+ vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
+ if (!vaddr)
+ return ERR_PTR(-ENOMEM);
+
+ return vaddr;
+}
+
+static void dma_heap_buffer_destroy(struct heap_helper_buffer *buffer)
+{
+ if (buffer->vmap_cnt > 0) {
+ WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
+ vunmap(buffer->vaddr);
+ }
+
+ buffer->free(buffer);
+}
+
+static void *dma_heap_buffer_vmap_get(struct heap_helper_buffer *buffer)
+{
+ void *vaddr;
+
+ if (buffer->vmap_cnt) {
+ buffer->vmap_cnt++;
+ return buffer->vaddr;
+ }
+ vaddr = dma_heap_map_kernel(buffer);
+ if (IS_ERR(vaddr))
+ return vaddr;
+ buffer->vaddr = vaddr;
+ buffer->vmap_cnt++;
+ return vaddr;
+}
+
+static void dma_heap_buffer_vmap_put(struct heap_helper_buffer *buffer)
+{
+ if (!--buffer->vmap_cnt) {
+ vunmap(buffer->vaddr);
+ buffer->vaddr = NULL;
+ }
+}
+
+struct dma_heaps_attachment {
+ struct device *dev;
+ struct sg_table table;
+ struct list_head list;
+};
+
+static int dma_heap_attach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attachment)
+{
+ struct dma_heaps_attachment *a;
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+ int ret;
+
+ a = kzalloc(sizeof(*a), GFP_KERNEL);
+ if (!a)
+ return -ENOMEM;
+
+ ret = sg_alloc_table_from_pages(&a->table, buffer->pages,
+ buffer->pagecount, 0,
+ buffer->pagecount << PAGE_SHIFT,
+ GFP_KERNEL);
+ if (ret) {
+ kfree(a);
+ return ret;
+ }
+
+ a->dev = attachment->dev;
+ INIT_LIST_HEAD(&a->list);
+
+ attachment->priv = a;
+
+ mutex_lock(&buffer->lock);
+ list_add(&a->list, &buffer->attachments);
+ mutex_unlock(&buffer->lock);
+
+ return 0;
+}
+
+static void dma_heap_detach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attachment)
+{
+ struct dma_heaps_attachment *a = attachment->priv;
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+
+ mutex_lock(&buffer->lock);
+ list_del(&a->list);
+ mutex_unlock(&buffer->lock);
+
+ sg_free_table(&a->table);
+ kfree(a);
+}
+
+static
+struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment,
+ enum dma_data_direction direction)
+{
+ struct dma_heaps_attachment *a = attachment->priv;
+ struct sg_table *table;
+
+ table = &a->table;
+
+ if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
+ direction))
+ table = ERR_PTR(-ENOMEM);
+ return table;
+}
+
+static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
+ struct sg_table *table,
+ enum dma_data_direction direction)
+{
+ dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
+}
+
+static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct heap_helper_buffer *buffer = vma->vm_private_data;
+
+ if (vmf->pgoff > buffer->pagecount)
+ return VM_FAULT_SIGBUS;
+
+ vmf->page = buffer->pages[vmf->pgoff];
+ get_page(vmf->page);
+
+ return 0;
+}
+
+static const struct vm_operations_struct dma_heap_vm_ops = {
+ .fault = dma_heap_vm_fault,
+};
+
+static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
+{
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+
+ if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
+ return -EINVAL;
+
+ vma->vm_ops = &dma_heap_vm_ops;
+ vma->vm_private_data = buffer;
+
+ return 0;
+}
+
+static void dma_heap_dma_buf_release(struct dma_buf *dmabuf)
+{
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+
+ dma_heap_buffer_destroy(buffer);
+}
+
+static int dma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+ enum dma_data_direction direction)
+{
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+ struct dma_heaps_attachment *a;
+ int ret = 0;
+
+ mutex_lock(&buffer->lock);
+
+ if (buffer->vmap_cnt)
+ invalidate_kernel_vmap_range(buffer->vaddr, buffer->size);
+
+ list_for_each_entry(a, &buffer->attachments, list) {
+ dma_sync_sg_for_cpu(a->dev, a->table.sgl, a->table.nents,
+ direction);
+ }
+ mutex_unlock(&buffer->lock);
+
+ return ret;
+}
+
+static int dma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
+ enum dma_data_direction direction)
+{
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+ struct dma_heaps_attachment *a;
+
+ mutex_lock(&buffer->lock);
+
+ if (buffer->vmap_cnt)
+ flush_kernel_vmap_range(buffer->vaddr, buffer->size);
+
+ list_for_each_entry(a, &buffer->attachments, list) {
+ dma_sync_sg_for_device(a->dev, a->table.sgl, a->table.nents,
+ direction);
+ }
+ mutex_unlock(&buffer->lock);
+
+ return 0;
+}
+
+static void *dma_heap_dma_buf_vmap(struct dma_buf *dmabuf)
+{
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+ void *vaddr;
+
+ mutex_lock(&buffer->lock);
+ vaddr = dma_heap_buffer_vmap_get(buffer);
+ mutex_unlock(&buffer->lock);
+
+ return vaddr;
+}
+
+static void dma_heap_dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
+{
+ struct heap_helper_buffer *buffer = dmabuf->priv;
+
+ mutex_lock(&buffer->lock);
+ dma_heap_buffer_vmap_put(buffer);
+ mutex_unlock(&buffer->lock);
+}
+
+const struct dma_buf_ops heap_helper_ops = {
+ .map_dma_buf = dma_heap_map_dma_buf,
+ .unmap_dma_buf = dma_heap_unmap_dma_buf,
+ .mmap = dma_heap_mmap,
+ .release = dma_heap_dma_buf_release,
+ .attach = dma_heap_attach,
+ .detach = dma_heap_detach,
+ .begin_cpu_access = dma_heap_dma_buf_begin_cpu_access,
+ .end_cpu_access = dma_heap_dma_buf_end_cpu_access,
+ .vmap = dma_heap_dma_buf_vmap,
+ .vunmap = dma_heap_dma_buf_vunmap,
+};
diff --git a/drivers/dma-buf/heaps/heap-helpers.h b/drivers/dma-buf/heaps/heap-helpers.h
new file mode 100644
index 000000000000..911c931f7f06
--- /dev/null
+++ b/drivers/dma-buf/heaps/heap-helpers.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DMABUF Heaps helper code
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2019 Linaro Ltd.
+ */
+
+#ifndef _HEAP_HELPERS_H
+#define _HEAP_HELPERS_H
+
+#include <linux/dma-heap.h>
+#include <linux/list.h>
+
+/**
+ * struct heap_helper_buffer - helper buffer metadata
+ * @heap: back pointer to the heap the buffer came from
+ * @dmabuf: backing dma-buf for this buffer
+ * @size: size of the buffer
+ * @flags: buffer specific flags
+ * @priv_virt pointer to heap specific private value
+ * @lock mutext to protect the data in this structure
+ * @vmap_cnt count of vmap references on the buffer
+ * @vaddr vmap'ed virtual address
+ * @pagecount number of pages in the buffer
+ * @pages list of page pointers
+ * @attachments list of device attachments
+ *
+ * @free heap callback to free the buffer
+ */
+struct heap_helper_buffer {
+ struct dma_heap *heap;
+ struct dma_buf *dmabuf;
+ size_t size;
+ unsigned long flags;
+
+ void *priv_virt;
+ struct mutex lock;
+ int vmap_cnt;
+ void *vaddr;
+ pgoff_t pagecount;
+ struct page **pages;
+ struct list_head attachments;
+
+ void (*free)(struct heap_helper_buffer *buffer);
+};
+
+void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
+ void (*free)(struct heap_helper_buffer *));
+
+struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
+ int fd_flags);
+
+extern const struct dma_buf_ops heap_helper_ops;
+#endif /* _HEAP_HELPERS_H */
--
2.17.1
From: "Andrew F. Davis" <[email protected]>
This framework allows a unified userspace interface for dma-buf
exporters, allowing userland to allocate specific types of memory
for use in dma-buf sharing.
Each heap is given its own device node, which a user can allocate
a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.
Additionally should the interface grow in the future, we have a
DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
flags.
This code is an evoluiton of the Android ION implementation,
and a big thanks is due to its authors/maintainers over time
for their effort:
Rebecca Schultz Zavin, Colin Cross, Benjamin Gaignard,
Laura Abbott, and many other contributors!
Cc: Laura Abbott <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Pratik Patel <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Sudipto Paul <[email protected]>
Cc: Andrew F. Davis <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chenbo Feng <[email protected]>
Cc: Alistair Strachan <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Signed-off-by: Andrew F. Davis <[email protected]>
Signed-off-by: John Stultz <[email protected]>
---
v2:
* Folded down fixes I had previously shared in implementing
heaps
* Make flags a u64 (Suggested by Laura)
* Add PAGE_ALIGN() fix to the core alloc funciton
* IOCTL fixups suggested by Brian
* Added fixes suggested by Benjamin
* Removed core stats mgmt, as that should be implemented by
per-heap code
* Changed alloc to return a dma-buf fd, rather than a buffer
(as it simplifies error handling)
v3:
* Removed scare-quotes in MAINTAINERS email address
* Get rid of .release function as it didn't do anything (from
Christoph)
* Renamed filp to file (suggested by Christoph)
* Split out ioctl handling to separate function (suggested by
Christoph)
* Add comment documenting PAGE_ALIGN usage (suggested by Brian)
* Switch from idr to Xarray (suggested by Brian)
* Fixup cdev creation (suggested by Brian)
* Avoid EXPORT_SYMBOL until we finalize modules (suggested by
Brian)
* Make struct dma_heap internal only (folded in from Andrew)
* Small cleanups suggested by GregKH
* Provide class->devnode callback to get consistent /dev/
subdirectory naming (Suggested by Bjorn)
v4:
* Folded down dma-heap.h change that was in a following patch
* Added fd_flags entry to allocation structure and pass it
through to heap code for use on dma-buf fd creation (suggested
by Benjamin)
v5:
* Minor cleanups
v6:
* Improved error path handling, minor whitespace fixes, both
suggested by Brian
v7:
* Longer Kconfig description to quiet checkpatch warnings
* Re-add compat_ioctl bits (Hridya noticed 32bit userland wasn't
working)
v8:
* Make struct dma_heap_ops consts (Suggested by Christoph)
* Checkpatch whitespace fixups
v9:
* Minor cleanups suggested by Brian Starkey
* Rename dma_heap_get_data->dma_heap_get_drvdata suggested
by Hilf Danton
v11:
* Kconfig text improvements suggested by Randy Dunlap
v12:
* Add logic to prevent duplicately named heaps being added
* Add symbol exports for heaps as modules
v13:
* Re-remove symbol exports per discussion w/ Brian. Will
resubmit in a separte patch for review
v14:
* Reworked ioctl handler to zero fill any difference in
structure size, similar to what the DRM core does, as
suggested by Dave Airlie
* Removed now unnecessary reserved bits in allocate_data
* Added get_features ioctl as suggested by Dave Airlie
* Removed pr_warn_once messages as requested by Dave
Airlie
---
MAINTAINERS | 18 ++
drivers/dma-buf/Kconfig | 9 +
drivers/dma-buf/Makefile | 1 +
drivers/dma-buf/dma-heap.c | 313 ++++++++++++++++++++++++++++++++++
include/linux/dma-heap.h | 59 +++++++
include/uapi/linux/dma-heap.h | 77 +++++++++
6 files changed, 477 insertions(+)
create mode 100644 drivers/dma-buf/dma-heap.c
create mode 100644 include/linux/dma-heap.h
create mode 100644 include/uapi/linux/dma-heap.h
diff --git a/MAINTAINERS b/MAINTAINERS
index c6c34d04ce95..77c3e993fb2f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4940,6 +4940,24 @@ F: include/linux/*fence.h
F: Documentation/driver-api/dma-buf.rst
T: git git://anongit.freedesktop.org/drm/drm-misc
+DMA-BUF HEAPS FRAMEWORK
+M: Sumit Semwal <[email protected]>
+R: Andrew F. Davis <[email protected]>
+R: Benjamin Gaignard <[email protected]>
+R: Liam Mark <[email protected]>
+R: Laura Abbott <[email protected]>
+R: Brian Starkey <[email protected]>
+R: John Stultz <[email protected]>
+S: Maintained
+L: [email protected]
+L: [email protected]
+L: [email protected] (moderated for non-subscribers)
+F: include/uapi/linux/dma-heap.h
+F: include/linux/dma-heap.h
+F: drivers/dma-buf/dma-heap.c
+F: drivers/dma-buf/heaps/*
+T: git git://anongit.freedesktop.org/drm/drm-misc
+
DMA GENERIC OFFLOAD ENGINE SUBSYSTEM
M: Vinod Koul <[email protected]>
L: [email protected]
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index a23b6752d11a..bffa58fc3e6e 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -44,4 +44,13 @@ config DMABUF_SELFTESTS
default n
depends on DMA_SHARED_BUFFER
+menuconfig DMABUF_HEAPS
+ bool "DMA-BUF Userland Memory Heaps"
+ select DMA_SHARED_BUFFER
+ help
+ Choose this option to enable the DMA-BUF userland memory heaps.
+ This options creates per heap chardevs in /dev/dma_heap/ which
+ allows userspace to allocate dma-bufs that can be shared
+ between drivers.
+
endmenu
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index 03479da06422..caee5eb3d351 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
dma-resv.o seqno-fence.o
+obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
obj-$(CONFIG_SYNC_FILE) += sync_file.o
obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
obj-$(CONFIG_UDMABUF) += udmabuf.o
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
new file mode 100644
index 000000000000..7cdd7179e5fa
--- /dev/null
+++ b/drivers/dma-buf/dma-heap.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Framework for userspace DMA-BUF allocations
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2019 Linaro Ltd.
+ */
+
+#include <linux/cdev.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/err.h>
+#include <linux/xarray.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/dma-heap.h>
+#include <uapi/linux/dma-heap.h>
+
+#define DEVNAME "dma_heap"
+
+#define NUM_HEAP_MINORS 128
+
+/**
+ * struct dma_heap - represents a dmabuf heap in the system
+ * @name: used for debugging/device-node name
+ * @ops: ops struct for this heap
+ * @minor minor number of this heap device
+ * @heap_devt heap device node
+ * @heap_cdev heap char device
+ *
+ * Represents a heap of memory from which buffers can be made.
+ */
+struct dma_heap {
+ const char *name;
+ const struct dma_heap_ops *ops;
+ void *priv;
+ unsigned int minor;
+ dev_t heap_devt;
+ struct list_head list;
+ struct cdev heap_cdev;
+};
+
+static LIST_HEAD(heap_list);
+static DEFINE_MUTEX(heap_list_lock);
+static dev_t dma_heap_devt;
+static struct class *dma_heap_class;
+static DEFINE_XARRAY_ALLOC(dma_heap_minors);
+
+static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
+ unsigned int fd_flags,
+ unsigned int heap_flags)
+{
+ /*
+ * Allocations from all heaps have to begin
+ * and end on page boundaries.
+ */
+ len = PAGE_ALIGN(len);
+ if (!len)
+ return -EINVAL;
+
+ return heap->ops->allocate(heap, len, fd_flags, heap_flags);
+}
+
+static int dma_heap_open(struct inode *inode, struct file *file)
+{
+ struct dma_heap *heap;
+
+ heap = xa_load(&dma_heap_minors, iminor(inode));
+ if (!heap) {
+ pr_err("dma_heap: minor %d unknown.\n", iminor(inode));
+ return -ENODEV;
+ }
+
+ /* instance data as context */
+ file->private_data = heap;
+ nonseekable_open(inode, file);
+
+ return 0;
+}
+
+static long dma_heap_ioctl_get_features(struct file *file, void *data)
+{
+ struct dma_heap_get_features_data *heap_features = data;
+
+ /* nothing should be passed in */
+ if (heap_features->features)
+ return -EINVAL;
+
+ heap_features->features = DMA_HEAP_SUPPORTED_FEATURES;
+ return 0;
+}
+
+static long dma_heap_ioctl_allocate(struct file *file, void *data)
+{
+ struct dma_heap_allocation_data *heap_allocation = data;
+ struct dma_heap *heap = file->private_data;
+ int fd;
+
+ if (heap_allocation->fd)
+ return -EINVAL;
+
+ if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
+ return -EINVAL;
+
+ if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
+ return -EINVAL;
+
+ fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
+ heap_allocation->fd_flags,
+ heap_allocation->heap_flags);
+ if (fd < 0)
+ return fd;
+
+ heap_allocation->fd = fd;
+
+ return 0;
+}
+
+unsigned int dma_heap_ioctl_cmds[] = {
+ DMA_HEAP_IOC_GET_FEATURES,
+ DMA_HEAP_IOC_ALLOC,
+};
+
+static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
+ unsigned long arg)
+{
+ char stack_kdata[128];
+ char *kdata = stack_kdata;
+ unsigned int kcmd;
+ unsigned int in_size, out_size, drv_size, ksize;
+ int nr = _IOC_NR(ucmd);
+ int ret = 0;
+
+ if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds))
+ return -EINVAL;
+
+ /* Get the kernel ioctl cmd that matches */
+ kcmd = dma_heap_ioctl_cmds[nr];
+
+ /* Figure out the delta between user cmd size and kernel cmd size */
+ drv_size = _IOC_SIZE(kcmd);
+ out_size = _IOC_SIZE(ucmd);
+ in_size = out_size;
+ if ((ucmd & kcmd & IOC_IN) == 0)
+ in_size = 0;
+ if ((ucmd & kcmd & IOC_OUT) == 0)
+ out_size = 0;
+ ksize = max(max(in_size, out_size), drv_size);
+
+ /* If necessary, allocate buffer for ioctl argument */
+ if (ksize > sizeof(stack_kdata)) {
+ kdata = kmalloc(ksize, GFP_KERNEL);
+ if (!kdata)
+ return -ENOMEM;
+ }
+
+ if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ /* zero out any difference between the kernel/user structure size */
+ if (ksize > in_size)
+ memset(kdata + in_size, 0, ksize - in_size);
+
+ switch (kcmd) {
+ case DMA_HEAP_IOC_GET_FEATURES:
+ ret = dma_heap_ioctl_get_features(file, kdata);
+ break;
+ case DMA_HEAP_IOC_ALLOC:
+ ret = dma_heap_ioctl_allocate(file, kdata);
+ break;
+ default:
+ return -ENOTTY;
+ }
+
+ if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
+ ret = -EFAULT;
+err:
+ if (kdata != stack_kdata)
+ kfree(kdata);
+ return ret;
+}
+
+static const struct file_operations dma_heap_fops = {
+ .owner = THIS_MODULE,
+ .open = dma_heap_open,
+ .unlocked_ioctl = dma_heap_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = dma_heap_ioctl,
+#endif
+};
+
+/**
+ * dma_heap_get_drvdata() - get per-subdriver data for the heap
+ * @heap: DMA-Heap to retrieve private data for
+ *
+ * Returns:
+ * The per-subdriver data for the heap.
+ */
+void *dma_heap_get_drvdata(struct dma_heap *heap)
+{
+ return heap->priv;
+}
+
+struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
+{
+ struct dma_heap *heap, *h, *err_ret;
+ struct device *dev_ret;
+ int ret;
+
+ if (!exp_info->name || !strcmp(exp_info->name, "")) {
+ pr_err("dma_heap: Cannot add heap without a name\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (!exp_info->ops || !exp_info->ops->allocate) {
+ pr_err("dma_heap: Cannot add heap with invalid ops struct\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ /* check the name is unique */
+ mutex_lock(&heap_list_lock);
+ list_for_each_entry(h, &heap_list, list) {
+ if (!strcmp(h->name, exp_info->name)) {
+ mutex_unlock(&heap_list_lock);
+ pr_err("dma_heap: Already registered heap named %s\n",
+ exp_info->name);
+ return ERR_PTR(-EINVAL);
+ }
+ }
+ mutex_unlock(&heap_list_lock);
+
+ heap = kzalloc(sizeof(*heap), GFP_KERNEL);
+ if (!heap)
+ return ERR_PTR(-ENOMEM);
+
+ heap->name = exp_info->name;
+ heap->ops = exp_info->ops;
+ heap->priv = exp_info->priv;
+
+ /* Find unused minor number */
+ ret = xa_alloc(&dma_heap_minors, &heap->minor, heap,
+ XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL);
+ if (ret < 0) {
+ pr_err("dma_heap: Unable to get minor number for heap\n");
+ err_ret = ERR_PTR(ret);
+ goto err0;
+ }
+
+ /* Create device */
+ heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor);
+
+ cdev_init(&heap->heap_cdev, &dma_heap_fops);
+ ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1);
+ if (ret < 0) {
+ pr_err("dma_heap: Unable to add char device\n");
+ err_ret = ERR_PTR(ret);
+ goto err1;
+ }
+
+ dev_ret = device_create(dma_heap_class,
+ NULL,
+ heap->heap_devt,
+ NULL,
+ heap->name);
+ if (IS_ERR(dev_ret)) {
+ pr_err("dma_heap: Unable to create device\n");
+ err_ret = ERR_CAST(dev_ret);
+ goto err2;
+ }
+ /* Add heap to the list */
+ mutex_lock(&heap_list_lock);
+ list_add(&heap->list, &heap_list);
+ mutex_unlock(&heap_list_lock);
+
+ return heap;
+
+err2:
+ cdev_del(&heap->heap_cdev);
+err1:
+ xa_erase(&dma_heap_minors, heap->minor);
+err0:
+ kfree(heap);
+ return err_ret;
+}
+
+static char *dma_heap_devnode(struct device *dev, umode_t *mode)
+{
+ return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev));
+}
+
+static int dma_heap_init(void)
+{
+ int ret;
+
+ ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
+ if (ret)
+ return ret;
+
+ dma_heap_class = class_create(THIS_MODULE, DEVNAME);
+ if (IS_ERR(dma_heap_class)) {
+ unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
+ return PTR_ERR(dma_heap_class);
+ }
+ dma_heap_class->devnode = dma_heap_devnode;
+
+ return 0;
+}
+subsys_initcall(dma_heap_init);
diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
new file mode 100644
index 000000000000..454e354d1ffb
--- /dev/null
+++ b/include/linux/dma-heap.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DMABUF Heaps Allocation Infrastructure
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2019 Linaro Ltd.
+ */
+
+#ifndef _DMA_HEAPS_H
+#define _DMA_HEAPS_H
+
+#include <linux/cdev.h>
+#include <linux/types.h>
+
+struct dma_heap;
+
+/**
+ * struct dma_heap_ops - ops to operate on a given heap
+ * @allocate: allocate dmabuf and return fd
+ *
+ * allocate returns dmabuf fd on success, -errno on error.
+ */
+struct dma_heap_ops {
+ int (*allocate)(struct dma_heap *heap,
+ unsigned long len,
+ unsigned long fd_flags,
+ unsigned long heap_flags);
+};
+
+/**
+ * struct dma_heap_export_info - information needed to export a new dmabuf heap
+ * @name: used for debugging/device-node name
+ * @ops: ops struct for this heap
+ * @priv: heap exporter private data
+ *
+ * Information needed to export a new dmabuf heap.
+ */
+struct dma_heap_export_info {
+ const char *name;
+ const struct dma_heap_ops *ops;
+ void *priv;
+};
+
+/**
+ * dma_heap_get_drvdata() - get per-heap driver data
+ * @heap: DMA-Heap to retrieve private data for
+ *
+ * Returns:
+ * The per-heap data for the heap.
+ */
+void *dma_heap_get_drvdata(struct dma_heap *heap);
+
+/**
+ * dma_heap_add - adds a heap to dmabuf heaps
+ * @exp_info: information needed to register this heap
+ */
+struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
+
+#endif /* _DMA_HEAPS_H */
diff --git a/include/uapi/linux/dma-heap.h b/include/uapi/linux/dma-heap.h
new file mode 100644
index 000000000000..22f620991758
--- /dev/null
+++ b/include/uapi/linux/dma-heap.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * DMABUF Heaps Userspace API
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2019 Linaro Ltd.
+ */
+#ifndef _UAPI_LINUX_DMABUF_POOL_H
+#define _UAPI_LINUX_DMABUF_POOL_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/**
+ * DOC: DMABUF Heaps Userspace API
+ */
+
+#define DMA_HEAP_FEATURE_NONE (0x0)
+
+/* Currrently no supported features */
+#define DMA_HEAP_SUPPORTED_FEATURES (DMA_HEAP_FEATURE_NONE)
+
+/**
+ * struct dma_heap_get_features_data - metadata passed from userspace for
+ * getting interface features
+ * @features: features flag returned from kernel
+ *
+ * Provided by userspace as an argument to the ioctl
+ */
+struct dma_heap_get_features_data {
+ __u64 features;
+};
+
+/* Valid FD_FLAGS are O_CLOEXEC, O_RDONLY, O_WRONLY, O_RDWR */
+#define DMA_HEAP_VALID_FD_FLAGS (O_CLOEXEC | O_ACCMODE)
+
+/* Currently no heap flags */
+#define DMA_HEAP_VALID_HEAP_FLAGS (0)
+
+/**
+ * struct dma_heap_allocation_data - metadata passed from userspace for
+ * allocations
+ * @len: size of the allocation
+ * @fd: will be populated with a fd which provdes the
+ * handle to the allocated dma-buf
+ * @fd_flags: file descriptor flags used when allocating
+ * @heap_flags: flags passed to heap
+ *
+ * Provided by userspace as an argument to the ioctl
+ */
+struct dma_heap_allocation_data {
+ __u64 len;
+ __u32 fd;
+ __u32 fd_flags;
+ __u64 heap_flags;
+};
+
+#define DMA_HEAP_IOC_MAGIC 'H'
+
+/**
+ * DOC: DMA_HEAP_IOC_GET_FEATURES - Get interface features
+ *
+ * Takes an dma_heap_features_data struct and returns it with the features
+ * flages set with the interfaces supported features.
+ */
+#define DMA_HEAP_IOC_GET_FEATURES _IOR(DMA_HEAP_IOC_MAGIC, 0x0,\
+ struct dma_heap_get_features_data)
+/**
+ * DOC: DMA_HEAP_IOC_ALLOC - allocate memory from pool
+ *
+ * Takes an dma_heap_allocation_data struct and returns it with the fd field
+ * populated with the dmabuf handle of the allocation.
+ */
+#define DMA_HEAP_IOC_ALLOC _IOWR(DMA_HEAP_IOC_MAGIC, 0x1,\
+ struct dma_heap_allocation_data)
+
+#endif /* _UAPI_LINUX_DMABUF_POOL_H */
--
2.17.1
This adds a CMA heap, which allows userspace to allocate
a dma-buf of contiguous memory out of a CMA region.
This code is an evolution of the Android ION implementation, so
thanks to its original author and maintainters:
Benjamin Gaignard, Laura Abbott, and others!
NOTE: This patch only adds the default CMA heap. We will enable
selectively adding other CMA memory regions to the dmabuf heaps
interface with a later patch (which requires a dt binding)
Cc: Laura Abbott <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Pratik Patel <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Sudipto Paul <[email protected]>
Cc: Andrew F. Davis <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chenbo Feng <[email protected]>
Cc: Alistair Strachan <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Reviewed-by: Benjamin Gaignard <[email protected]>
Reviewed-by: Brian Starkey <[email protected]>
Acked-by: Laura Abbott <[email protected]>
Tested-by: Ayan Kumar Halder <[email protected]>
Signed-off-by: John Stultz <[email protected]>
---
v2:
* Switch allocate to return dmabuf fd
* Simplify init code
* Checkpatch fixups
v3:
* Switch to inline function for to_cma_heap()
* Minor cleanups suggested by Brian
* Fold in new registration style from Andrew
* Folded in changes from Andrew to use simplified page list
from the heap helpers
v4:
* Use the fd_flags when creating dmabuf fd (Suggested by
Benjamin)
* Use precalculated pagecount (Suggested by Andrew)
v6:
* Changed variable names to improve clarity, as suggested
by Brian
v7:
* Use newly lower-cased init_heap_helper_buffer helper
* Use new dmabuf export helper
v8:
* Make struct dma_heap_ops const (Suggested by Christoph)
* Condense dma_heap_buffer and heap_helper_buffer (suggested by
Christoph)
* Checkpatch whitespace fixups
v9:
* Removing needless check noted by Brian Starkey
* Rename dma_heap_get_data->dma_heap_get_drvdata suggested
by Hilf Danton
* Check signals after clearing memory pages to avoid doing
needless work if the task is killed as suggested by Hilf
v12:
* Rework to only add the default CMA heap
---
drivers/dma-buf/heaps/Kconfig | 8 ++
drivers/dma-buf/heaps/Makefile | 1 +
drivers/dma-buf/heaps/cma_heap.c | 178 +++++++++++++++++++++++++++++++
3 files changed, 187 insertions(+)
create mode 100644 drivers/dma-buf/heaps/cma_heap.c
diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index 205052744169..a5eef06c4226 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -4,3 +4,11 @@ config DMABUF_HEAPS_SYSTEM
help
Choose this option to enable the system dmabuf heap. The system heap
is backed by pages from the buddy allocator. If in doubt, say Y.
+
+config DMABUF_HEAPS_CMA
+ bool "DMA-BUF CMA Heap"
+ depends on DMABUF_HEAPS && DMA_CMA
+ help
+ Choose this option to enable dma-buf CMA heap. This heap is backed
+ by the Contiguous Memory Allocator (CMA). If your system has these
+ regions, you should say Y here.
diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
index d1808eca2581..6e54cdec3da0 100644
--- a/drivers/dma-buf/heaps/Makefile
+++ b/drivers/dma-buf/heaps/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-y += heap-helpers.o
obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o
+obj-$(CONFIG_DMABUF_HEAPS_CMA) += cma_heap.o
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
new file mode 100644
index 000000000000..064926b5d735
--- /dev/null
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DMABUF CMA heap exporter
+ *
+ * Copyright (C) 2012, 2019 Linaro Ltd.
+ * Author: <[email protected]> for ST-Ericsson.
+ */
+
+#include <linux/cma.h>
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-heap.h>
+#include <linux/dma-contiguous.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/scatterlist.h>
+#include <linux/sched/signal.h>
+
+#include "heap-helpers.h"
+
+struct cma_heap {
+ struct dma_heap *heap;
+ struct cma *cma;
+};
+
+static void cma_heap_free(struct heap_helper_buffer *buffer)
+{
+ struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
+ unsigned long nr_pages = buffer->pagecount;
+ struct page *cma_pages = buffer->priv_virt;
+
+ /* free page list */
+ kfree(buffer->pages);
+ /* release memory */
+ cma_release(cma_heap->cma, cma_pages, nr_pages);
+ kfree(buffer);
+}
+
+/* dmabuf heap CMA operations functions */
+static int cma_heap_allocate(struct dma_heap *heap,
+ unsigned long len,
+ unsigned long fd_flags,
+ unsigned long heap_flags)
+{
+ struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
+ struct heap_helper_buffer *helper_buffer;
+ struct page *cma_pages;
+ size_t size = PAGE_ALIGN(len);
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ unsigned long align = get_order(size);
+ struct dma_buf *dmabuf;
+ int ret = -ENOMEM;
+ pgoff_t pg;
+
+ if (align > CONFIG_CMA_ALIGNMENT)
+ align = CONFIG_CMA_ALIGNMENT;
+
+ helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
+ if (!helper_buffer)
+ return -ENOMEM;
+
+ init_heap_helper_buffer(helper_buffer, cma_heap_free);
+ helper_buffer->flags = heap_flags;
+ helper_buffer->heap = heap;
+ helper_buffer->size = len;
+
+ cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
+ if (!cma_pages)
+ goto free_buf;
+
+ if (PageHighMem(cma_pages)) {
+ unsigned long nr_clear_pages = nr_pages;
+ struct page *page = cma_pages;
+
+ while (nr_clear_pages > 0) {
+ void *vaddr = kmap_atomic(page);
+
+ memset(vaddr, 0, PAGE_SIZE);
+ kunmap_atomic(vaddr);
+ /*
+ * Avoid wasting time zeroing memory if the process
+ * has been killed by by SIGKILL
+ */
+ if (fatal_signal_pending(current))
+ goto free_cma;
+
+ page++;
+ nr_clear_pages--;
+ }
+ } else {
+ memset(page_address(cma_pages), 0, size);
+ }
+
+ helper_buffer->pagecount = nr_pages;
+ helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
+ sizeof(*helper_buffer->pages),
+ GFP_KERNEL);
+ if (!helper_buffer->pages) {
+ ret = -ENOMEM;
+ goto free_cma;
+ }
+
+ for (pg = 0; pg < helper_buffer->pagecount; pg++)
+ helper_buffer->pages[pg] = &cma_pages[pg];
+
+ /* create the dmabuf */
+ dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+ if (IS_ERR(dmabuf)) {
+ ret = PTR_ERR(dmabuf);
+ goto free_pages;
+ }
+
+ helper_buffer->dmabuf = dmabuf;
+ helper_buffer->priv_virt = cma_pages;
+
+ ret = dma_buf_fd(dmabuf, fd_flags);
+ if (ret < 0) {
+ dma_buf_put(dmabuf);
+ /* just return, as put will call release and that will free */
+ return ret;
+ }
+
+ return ret;
+
+free_pages:
+ kfree(helper_buffer->pages);
+free_cma:
+ cma_release(cma_heap->cma, cma_pages, nr_pages);
+free_buf:
+ kfree(helper_buffer);
+ return ret;
+}
+
+static const struct dma_heap_ops cma_heap_ops = {
+ .allocate = cma_heap_allocate,
+};
+
+static int __add_cma_heap(struct cma *cma, void *data)
+{
+ struct cma_heap *cma_heap;
+ struct dma_heap_export_info exp_info;
+
+ cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
+ if (!cma_heap)
+ return -ENOMEM;
+ cma_heap->cma = cma;
+
+ exp_info.name = cma_get_name(cma);
+ exp_info.ops = &cma_heap_ops;
+ exp_info.priv = cma_heap;
+
+ cma_heap->heap = dma_heap_add(&exp_info);
+ if (IS_ERR(cma_heap->heap)) {
+ int ret = PTR_ERR(cma_heap->heap);
+
+ kfree(cma_heap);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int add_default_cma_heap(void)
+{
+ struct cma *default_cma = dev_get_cma_area(NULL);
+ int ret = 0;
+
+ if (default_cma)
+ ret = __add_cma_heap(default_cma, NULL);
+
+ return ret;
+}
+module_init(add_default_cma_heap);
+MODULE_DESCRIPTION("DMA-BUF CMA Heap");
+MODULE_LICENSE("GPL v2");
--
2.17.1
Hi John,
Thanks a lot for doing this. I really hope we get to move to dmabuf based
heaps and away from ion for Android soon. One of the nice things this
implementation will give us is also to add granular SELinux based controls on
which components / processes of android get to allocate from a pre-defined,
generic set of heaps.
On Fri, Nov 01, 2019 at 09:42:34PM +0000, John Stultz wrote:
> From: "Andrew F. Davis" <[email protected]>
>
> This framework allows a unified userspace interface for dma-buf
> exporters, allowing userland to allocate specific types of memory
> for use in dma-buf sharing.
>
> Each heap is given its own device node, which a user can allocate
> a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.
>
> Additionally should the interface grow in the future, we have a
> DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
> flags.
>
> This code is an evoluiton of the Android ION implementation,
> and a big thanks is due to its authors/maintainers over time
> for their effort:
> Rebecca Schultz Zavin, Colin Cross, Benjamin Gaignard,
> Laura Abbott, and many other contributors!
>
> Cc: Laura Abbott <[email protected]>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
> Signed-off-by: Andrew F. Davis <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
I have a couple of nits below and one question about how you expect the
features check to work for uninitialized user space variables
Other than that, this LGTM.
Please feel free to add if you end up re-spinning this.
Acked-by: Sandeep Patil <[email protected]>
> ---
> v2:
> * Folded down fixes I had previously shared in implementing
> heaps
> * Make flags a u64 (Suggested by Laura)
> * Add PAGE_ALIGN() fix to the core alloc funciton
> * IOCTL fixups suggested by Brian
> * Added fixes suggested by Benjamin
> * Removed core stats mgmt, as that should be implemented by
> per-heap code
> * Changed alloc to return a dma-buf fd, rather than a buffer
> (as it simplifies error handling)
> v3:
> * Removed scare-quotes in MAINTAINERS email address
> * Get rid of .release function as it didn't do anything (from
> Christoph)
> * Renamed filp to file (suggested by Christoph)
> * Split out ioctl handling to separate function (suggested by
> Christoph)
> * Add comment documenting PAGE_ALIGN usage (suggested by Brian)
> * Switch from idr to Xarray (suggested by Brian)
> * Fixup cdev creation (suggested by Brian)
> * Avoid EXPORT_SYMBOL until we finalize modules (suggested by
> Brian)
> * Make struct dma_heap internal only (folded in from Andrew)
> * Small cleanups suggested by GregKH
> * Provide class->devnode callback to get consistent /dev/
> subdirectory naming (Suggested by Bjorn)
> v4:
> * Folded down dma-heap.h change that was in a following patch
> * Added fd_flags entry to allocation structure and pass it
> through to heap code for use on dma-buf fd creation (suggested
> by Benjamin)
> v5:
> * Minor cleanups
> v6:
> * Improved error path handling, minor whitespace fixes, both
> suggested by Brian
> v7:
> * Longer Kconfig description to quiet checkpatch warnings
> * Re-add compat_ioctl bits (Hridya noticed 32bit userland wasn't
> working)
> v8:
> * Make struct dma_heap_ops consts (Suggested by Christoph)
> * Checkpatch whitespace fixups
> v9:
> * Minor cleanups suggested by Brian Starkey
> * Rename dma_heap_get_data->dma_heap_get_drvdata suggested
> by Hilf Danton
> v11:
> * Kconfig text improvements suggested by Randy Dunlap
> v12:
> * Add logic to prevent duplicately named heaps being added
> * Add symbol exports for heaps as modules
> v13:
> * Re-remove symbol exports per discussion w/ Brian. Will
> resubmit in a separte patch for review
> v14:
> * Reworked ioctl handler to zero fill any difference in
> structure size, similar to what the DRM core does, as
> suggested by Dave Airlie
> * Removed now unnecessary reserved bits in allocate_data
> * Added get_features ioctl as suggested by Dave Airlie
> * Removed pr_warn_once messages as requested by Dave
> Airlie
> ---
> MAINTAINERS | 18 ++
> drivers/dma-buf/Kconfig | 9 +
> drivers/dma-buf/Makefile | 1 +
> drivers/dma-buf/dma-heap.c | 313 ++++++++++++++++++++++++++++++++++
> include/linux/dma-heap.h | 59 +++++++
> include/uapi/linux/dma-heap.h | 77 +++++++++
> 6 files changed, 477 insertions(+)
> create mode 100644 drivers/dma-buf/dma-heap.c
> create mode 100644 include/linux/dma-heap.h
> create mode 100644 include/uapi/linux/dma-heap.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c6c34d04ce95..77c3e993fb2f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4940,6 +4940,24 @@ F: include/linux/*fence.h
> F: Documentation/driver-api/dma-buf.rst
> T: git git://anongit.freedesktop.org/drm/drm-misc
>
> +DMA-BUF HEAPS FRAMEWORK
> +M: Sumit Semwal <[email protected]>
> +R: Andrew F. Davis <[email protected]>
> +R: Benjamin Gaignard <[email protected]>
> +R: Liam Mark <[email protected]>
> +R: Laura Abbott <[email protected]>
> +R: Brian Starkey <[email protected]>
> +R: John Stultz <[email protected]>
> +S: Maintained
> +L: [email protected]
> +L: [email protected]
> +L: [email protected] (moderated for non-subscribers)
> +F: include/uapi/linux/dma-heap.h
> +F: include/linux/dma-heap.h
> +F: drivers/dma-buf/dma-heap.c
> +F: drivers/dma-buf/heaps/*
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +
> DMA GENERIC OFFLOAD ENGINE SUBSYSTEM
> M: Vinod Koul <[email protected]>
> L: [email protected]
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index a23b6752d11a..bffa58fc3e6e 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -44,4 +44,13 @@ config DMABUF_SELFTESTS
> default n
> depends on DMA_SHARED_BUFFER
>
nit: whitespace
> +menuconfig DMABUF_HEAPS
> + bool "DMA-BUF Userland Memory Heaps"
> + select DMA_SHARED_BUFFER
> + help
> + Choose this option to enable the DMA-BUF userland memory heaps.
> + This options creates per heap chardevs in /dev/dma_heap/ which
> + allows userspace to allocate dma-bufs that can be shared
> + between drivers.
> +
> endmenu
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> index 03479da06422..caee5eb3d351 100644
> --- a/drivers/dma-buf/Makefile
> +++ b/drivers/dma-buf/Makefile
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
> obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
> dma-resv.o seqno-fence.o
> +obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
> obj-$(CONFIG_SYNC_FILE) += sync_file.o
> obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
> obj-$(CONFIG_UDMABUF) += udmabuf.o
> diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
> new file mode 100644
> index 000000000000..7cdd7179e5fa
> --- /dev/null
> +++ b/drivers/dma-buf/dma-heap.c
> @@ -0,0 +1,313 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Framework for userspace DMA-BUF allocations
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +
> +#include <linux/cdev.h>
> +#include <linux/debugfs.h>
> +#include <linux/device.h>
> +#include <linux/dma-buf.h>
> +#include <linux/err.h>
> +#include <linux/xarray.h>
> +#include <linux/list.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +#include <linux/syscalls.h>
> +#include <linux/dma-heap.h>
> +#include <uapi/linux/dma-heap.h>
> +
> +#define DEVNAME "dma_heap"
> +
> +#define NUM_HEAP_MINORS 128
> +
> +/**
> + * struct dma_heap - represents a dmabuf heap in the system
> + * @name: used for debugging/device-node name
> + * @ops: ops struct for this heap
> + * @minor minor number of this heap device
> + * @heap_devt heap device node
> + * @heap_cdev heap char device
> + *
> + * Represents a heap of memory from which buffers can be made.
> + */
> +struct dma_heap {
> + const char *name;
> + const struct dma_heap_ops *ops;
> + void *priv;
> + unsigned int minor;
nit: do you need this one in the presence of the heap_devt below?
'minor' can just as easily by a local in the dmabuf_heap_add() function
below and for any code that comes after, we can extract it from 'heap_devt'.
> + dev_t heap_devt;
> + struct list_head list;
nit: what is the list for? May be a different name and a comment above
will be nice?
> + struct cdev heap_cdev;
> +};
> +
> +static LIST_HEAD(heap_list);
> +static DEFINE_MUTEX(heap_list_lock);
> +static dev_t dma_heap_devt;
> +static struct class *dma_heap_class;
> +static DEFINE_XARRAY_ALLOC(dma_heap_minors);
> +
> +static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
> + unsigned int fd_flags,
> + unsigned int heap_flags)
> +{
> + /*
> + * Allocations from all heaps have to begin
> + * and end on page boundaries.
> + */
> + len = PAGE_ALIGN(len);
> + if (!len)
> + return -EINVAL;
> +
> + return heap->ops->allocate(heap, len, fd_flags, heap_flags);
> +}
> +
> +static int dma_heap_open(struct inode *inode, struct file *file)
> +{
> + struct dma_heap *heap;
> +
> + heap = xa_load(&dma_heap_minors, iminor(inode));
> + if (!heap) {
> + pr_err("dma_heap: minor %d unknown.\n", iminor(inode));
> + return -ENODEV;
> + }
> +
> + /* instance data as context */
> + file->private_data = heap;
> + nonseekable_open(inode, file);
> +
> + return 0;
> +}
> +
> +static long dma_heap_ioctl_get_features(struct file *file, void *data)
> +{
> + struct dma_heap_get_features_data *heap_features = data;
> +
> + /* nothing should be passed in */
> + if (heap_features->features)
> + return -EINVAL;
curious, what are we trying to protect here? Unless I misunderstood this, you
are forcing userspace to 0 initialize the structure passed into the ioctl.
So an uninitialized stack variable passed into ioctl() will end up returning
-EINVAL .. I am not sure thats ok?
Plus, the point is pointing into the kmalloc'ed memory or the local 'char
stack_data[128] from the ioctl() function, so not sure if this check was
intentional? If so, may be easier to 0 initialize *kdata in the ioctl
function below?
> +
> + heap_features->features = DMA_HEAP_SUPPORTED_FEATURES;
> + return 0;
> +}
> +
> +static long dma_heap_ioctl_allocate(struct file *file, void *data)
> +{
> + struct dma_heap_allocation_data *heap_allocation = data;
> + struct dma_heap *heap = file->private_data;
> + int fd;
> +
> + if (heap_allocation->fd)
> + return -EINVAL;
> +
> + if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
> + return -EINVAL;
> +
> + if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
> + return -EINVAL;
> +
> + fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
> + heap_allocation->fd_flags,
> + heap_allocation->heap_flags);
> + if (fd < 0)
> + return fd;
> +
> + heap_allocation->fd = fd;
> +
> + return 0;
> +}
> +
> +unsigned int dma_heap_ioctl_cmds[] = {
> + DMA_HEAP_IOC_GET_FEATURES,
> + DMA_HEAP_IOC_ALLOC,
> +};
> +
> +static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
> + unsigned long arg)
> +{
> + char stack_kdata[128];
> + char *kdata = stack_kdata;
> + unsigned int kcmd;
> + unsigned int in_size, out_size, drv_size, ksize;
> + int nr = _IOC_NR(ucmd);
> + int ret = 0;
> +
> + if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds))
> + return -EINVAL;
> +
> + /* Get the kernel ioctl cmd that matches */
> + kcmd = dma_heap_ioctl_cmds[nr];
> +
> + /* Figure out the delta between user cmd size and kernel cmd size */
> + drv_size = _IOC_SIZE(kcmd);
> + out_size = _IOC_SIZE(ucmd);
> + in_size = out_size;
> + if ((ucmd & kcmd & IOC_IN) == 0)
> + in_size = 0;
> + if ((ucmd & kcmd & IOC_OUT) == 0)
> + out_size = 0;
> + ksize = max(max(in_size, out_size), drv_size);
> +
> + /* If necessary, allocate buffer for ioctl argument */
> + if (ksize > sizeof(stack_kdata)) {
> + kdata = kmalloc(ksize, GFP_KERNEL);
> + if (!kdata)
> + return -ENOMEM;
> + }
> +
> + if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
> + ret = -EFAULT;
> + goto err;
> + }
> +
> + /* zero out any difference between the kernel/user structure size */
> + if (ksize > in_size)
> + memset(kdata + in_size, 0, ksize - in_size);
> +
> + switch (kcmd) {
> + case DMA_HEAP_IOC_GET_FEATURES:
> + ret = dma_heap_ioctl_get_features(file, kdata);
> + break;
> + case DMA_HEAP_IOC_ALLOC:
> + ret = dma_heap_ioctl_allocate(file, kdata);
> + break;
> + default:
> + return -ENOTTY;
> + }
> +
> + if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
> + ret = -EFAULT;
> +err:
> + if (kdata != stack_kdata)
> + kfree(kdata);
> + return ret;
> +}
> +
> +static const struct file_operations dma_heap_fops = {
> + .owner = THIS_MODULE,
> + .open = dma_heap_open,
> + .unlocked_ioctl = dma_heap_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = dma_heap_ioctl,
> +#endif
> +};
> +
> +/**
> + * dma_heap_get_drvdata() - get per-subdriver data for the heap
> + * @heap: DMA-Heap to retrieve private data for
> + *
> + * Returns:
> + * The per-subdriver data for the heap.
> + */
> +void *dma_heap_get_drvdata(struct dma_heap *heap)
> +{
> + return heap->priv;
> +}
> +
> +struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
> +{
> + struct dma_heap *heap, *h, *err_ret;
> + struct device *dev_ret;
> + int ret;
> +
> + if (!exp_info->name || !strcmp(exp_info->name, "")) {
> + pr_err("dma_heap: Cannot add heap without a name\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (!exp_info->ops || !exp_info->ops->allocate) {
> + pr_err("dma_heap: Cannot add heap with invalid ops struct\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + /* check the name is unique */
> + mutex_lock(&heap_list_lock);
> + list_for_each_entry(h, &heap_list, list) {
> + if (!strcmp(h->name, exp_info->name)) {
> + mutex_unlock(&heap_list_lock);
> + pr_err("dma_heap: Already registered heap named %s\n",
> + exp_info->name);
> + return ERR_PTR(-EINVAL);
> + }
> + }
> + mutex_unlock(&heap_list_lock);
> +
> + heap = kzalloc(sizeof(*heap), GFP_KERNEL);
> + if (!heap)
> + return ERR_PTR(-ENOMEM);
> +
> + heap->name = exp_info->name;
> + heap->ops = exp_info->ops;
> + heap->priv = exp_info->priv;
> +
> + /* Find unused minor number */
> + ret = xa_alloc(&dma_heap_minors, &heap->minor, heap,
> + XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL);
> + if (ret < 0) {
> + pr_err("dma_heap: Unable to get minor number for heap\n");
> + err_ret = ERR_PTR(ret);
> + goto err0;
> + }
> +
> + /* Create device */
> + heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor);
> +
> + cdev_init(&heap->heap_cdev, &dma_heap_fops);
> + ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1);
> + if (ret < 0) {
> + pr_err("dma_heap: Unable to add char device\n");
> + err_ret = ERR_PTR(ret);
> + goto err1;
> + }
> +
> + dev_ret = device_create(dma_heap_class,
> + NULL,
> + heap->heap_devt,
> + NULL,
> + heap->name);
> + if (IS_ERR(dev_ret)) {
> + pr_err("dma_heap: Unable to create device\n");
> + err_ret = ERR_CAST(dev_ret);
> + goto err2;
> + }
> + /* Add heap to the list */
> + mutex_lock(&heap_list_lock);
> + list_add(&heap->list, &heap_list);
> + mutex_unlock(&heap_list_lock);
> +
> + return heap;
> +
> +err2:
> + cdev_del(&heap->heap_cdev);
> +err1:
> + xa_erase(&dma_heap_minors, heap->minor);
> +err0:
> + kfree(heap);
> + return err_ret;
> +}
> +
> +static char *dma_heap_devnode(struct device *dev, umode_t *mode)
> +{
> + return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev));
> +}
> +
> +static int dma_heap_init(void)
> +{
> + int ret;
> +
> + ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
> + if (ret)
> + return ret;
> +
> + dma_heap_class = class_create(THIS_MODULE, DEVNAME);
> + if (IS_ERR(dma_heap_class)) {
> + unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
> + return PTR_ERR(dma_heap_class);
> + }
> + dma_heap_class->devnode = dma_heap_devnode;
> +
> + return 0;
> +}
> +subsys_initcall(dma_heap_init);
> diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
> new file mode 100644
> index 000000000000..454e354d1ffb
> --- /dev/null
> +++ b/include/linux/dma-heap.h
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * DMABUF Heaps Allocation Infrastructure
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +
> +#ifndef _DMA_HEAPS_H
> +#define _DMA_HEAPS_H
> +
> +#include <linux/cdev.h>
> +#include <linux/types.h>
> +
> +struct dma_heap;
> +
> +/**
> + * struct dma_heap_ops - ops to operate on a given heap
> + * @allocate: allocate dmabuf and return fd
> + *
> + * allocate returns dmabuf fd on success, -errno on error.
> + */
> +struct dma_heap_ops {
> + int (*allocate)(struct dma_heap *heap,
> + unsigned long len,
> + unsigned long fd_flags,
> + unsigned long heap_flags);
> +};
> +
> +/**
> + * struct dma_heap_export_info - information needed to export a new dmabuf heap
> + * @name: used for debugging/device-node name
> + * @ops: ops struct for this heap
> + * @priv: heap exporter private data
> + *
> + * Information needed to export a new dmabuf heap.
> + */
> +struct dma_heap_export_info {
> + const char *name;
> + const struct dma_heap_ops *ops;
> + void *priv;
> +};
> +
> +/**
> + * dma_heap_get_drvdata() - get per-heap driver data
> + * @heap: DMA-Heap to retrieve private data for
> + *
> + * Returns:
> + * The per-heap data for the heap.
> + */
> +void *dma_heap_get_drvdata(struct dma_heap *heap);
> +
> +/**
> + * dma_heap_add - adds a heap to dmabuf heaps
> + * @exp_info: information needed to register this heap
> + */
> +struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
> +
> +#endif /* _DMA_HEAPS_H */
> diff --git a/include/uapi/linux/dma-heap.h b/include/uapi/linux/dma-heap.h
> new file mode 100644
> index 000000000000..22f620991758
> --- /dev/null
> +++ b/include/uapi/linux/dma-heap.h
> @@ -0,0 +1,77 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * DMABUF Heaps Userspace API
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +#ifndef _UAPI_LINUX_DMABUF_POOL_H
> +#define _UAPI_LINUX_DMABUF_POOL_H
> +
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +/**
> + * DOC: DMABUF Heaps Userspace API
> + */
> +
> +#define DMA_HEAP_FEATURE_NONE (0x0)
> +
> +/* Currrently no supported features */
> +#define DMA_HEAP_SUPPORTED_FEATURES (DMA_HEAP_FEATURE_NONE)
> +
> +/**
> + * struct dma_heap_get_features_data - metadata passed from userspace for
> + * getting interface features
> + * @features: features flag returned from kernel
> + *
> + * Provided by userspace as an argument to the ioctl
> + */
> +struct dma_heap_get_features_data {
> + __u64 features;
> +};
> +
> +/* Valid FD_FLAGS are O_CLOEXEC, O_RDONLY, O_WRONLY, O_RDWR */
> +#define DMA_HEAP_VALID_FD_FLAGS (O_CLOEXEC | O_ACCMODE)
> +
> +/* Currently no heap flags */
> +#define DMA_HEAP_VALID_HEAP_FLAGS (0)
> +
> +/**
> + * struct dma_heap_allocation_data - metadata passed from userspace for
> + * allocations
> + * @len: size of the allocation
> + * @fd: will be populated with a fd which provdes the
> + * handle to the allocated dma-buf
> + * @fd_flags: file descriptor flags used when allocating
> + * @heap_flags: flags passed to heap
> + *
> + * Provided by userspace as an argument to the ioctl
> + */
> +struct dma_heap_allocation_data {
> + __u64 len;
> + __u32 fd;
> + __u32 fd_flags;
> + __u64 heap_flags;
> +};
> +
> +#define DMA_HEAP_IOC_MAGIC 'H'
> +
> +/**
> + * DOC: DMA_HEAP_IOC_GET_FEATURES - Get interface features
> + *
> + * Takes an dma_heap_features_data struct and returns it with the features
> + * flages set with the interfaces supported features.
> + */
> +#define DMA_HEAP_IOC_GET_FEATURES _IOR(DMA_HEAP_IOC_MAGIC, 0x0,\
> + struct dma_heap_get_features_data)
> +/**
> + * DOC: DMA_HEAP_IOC_ALLOC - allocate memory from pool
> + *
> + * Takes an dma_heap_allocation_data struct and returns it with the fd field
> + * populated with the dmabuf handle of the allocation.
> + */
> +#define DMA_HEAP_IOC_ALLOC _IOWR(DMA_HEAP_IOC_MAGIC, 0x1,\
> + struct dma_heap_allocation_data)
> +
> +#endif /* _UAPI_LINUX_DMABUF_POOL_H */
> --
> 2.17.1
>
On Fri, Nov 01, 2019 at 09:42:35PM +0000, John Stultz wrote:
> Add generic helper dmabuf ops for dma heaps, so we can reduce
> the amount of duplicative code for the exported dmabufs.
>
> This code is an evolution of the Android ION implementation, so
> thanks to its original authors and maintainters:
> Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
>
> Cc: Laura Abbott <[email protected]>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
> Reviewed-by: Benjamin Gaignard <[email protected]>
> Reviewed-by: Brian Starkey <[email protected]>
> Acked-by: Laura Abbott <[email protected]>
> Tested-by: Ayan Kumar Halder <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
I have one question and a naming suggestin below (sorry).
Acked-by: Sandeep Patil <[email protected]>
> ---
> v2:
> * Removed cache management performance hack that I had
> accidentally folded in.
> * Removed stats code that was in helpers
> * Lots of checkpatch cleanups
> v3:
> * Uninline INIT_HEAP_HELPER_BUFFER (suggested by Christoph)
> * Switch to WARN on buffer destroy failure (suggested by Brian)
> * buffer->kmap_cnt decrementing cleanup (suggested by Christoph)
> * Extra buffer->vaddr checking in dma_heap_dma_buf_kmap
> (suggested by Brian)
> * Switch to_helper_buffer from macro to inline function
> (suggested by Benjamin)
> * Rename kmap->vmap (folded in from Andrew)
> * Use vmap for vmapping - not begin_cpu_access (folded in from
> Andrew)
> * Drop kmap for now, as its optional (folded in from Andrew)
> * Fold dma_heap_map_user into the single caller (foled in from
> Andrew)
> * Folded in patch from Andrew to track page list per heap not
> sglist, which simplifies the tracking logic
> v4:
> * Moved dma-heap.h change out to previous patch
> v6:
> * Minor cleanups and typo fixes suggested by Brian
> v7:
> * Removed stray ;
> * Make init_heap_helper_buffer lowercase, as suggested by Christoph
> * Add dmabuf export helper to reduce boilerplate code
> v8:
> * Remove unused private_flags value
> * Condense dma_heap_buffer and heap_helper_buffer (suggested by
> Christoph)
> * Fix indentation by using shorter argument names (suggested by
> Christoph)
> * Add flush_kernel_vmap_range/invalidate_kernel_vmap_range calls
> (suggested by Christoph)
> * Checkpatch whitespace fixups
> v9:
> * Minor cleanups suggested by Brian Starkey
> v10:
> * Fix missing vmalloc.h inclusion in heap helpers (found by
> kbuild test robot <[email protected]>)
> v12:
> * Add symbol exports for heaps as modules
> v13:
> * Re-remove symbol exports, per discussion with Brian, as I'll
> resubmit the change for review independently.
> v14:
> * Fix missing argment to WARN() in dma_heap_buffer_destroy()
> found and fixed by Dan Carpenter <[email protected]>
> * Add check in fault hanlder that pgoff isn't larger then
> pagecount, reported by Dan Carpenter
>
> ---
> drivers/dma-buf/Makefile | 1 +
> drivers/dma-buf/heaps/Makefile | 2 +
> drivers/dma-buf/heaps/heap-helpers.c | 271 +++++++++++++++++++++++++++
> drivers/dma-buf/heaps/heap-helpers.h | 55 ++++++
> 4 files changed, 329 insertions(+)
> create mode 100644 drivers/dma-buf/heaps/Makefile
> create mode 100644 drivers/dma-buf/heaps/heap-helpers.c
> create mode 100644 drivers/dma-buf/heaps/heap-helpers.h
>
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> index caee5eb3d351..9c190026bfab 100644
> --- a/drivers/dma-buf/Makefile
> +++ b/drivers/dma-buf/Makefile
> @@ -2,6 +2,7 @@
> obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
> dma-resv.o seqno-fence.o
> obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
> +obj-$(CONFIG_DMABUF_HEAPS) += heaps/
> obj-$(CONFIG_SYNC_FILE) += sync_file.o
> obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
> obj-$(CONFIG_UDMABUF) += udmabuf.o
> diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
> new file mode 100644
> index 000000000000..de49898112db
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +obj-y += heap-helpers.o
> diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c
> new file mode 100644
> index 000000000000..9f964ca3f59c
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/heap-helpers.c
> @@ -0,0 +1,271 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/device.h>
> +#include <linux/dma-buf.h>
> +#include <linux/err.h>
> +#include <linux/highmem.h>
> +#include <linux/idr.h>
> +#include <linux/list.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +#include <linux/vmalloc.h>
> +#include <uapi/linux/dma-heap.h>
> +
> +#include "heap-helpers.h"
> +
> +void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
> + void (*free)(struct heap_helper_buffer *))
> +{
> + buffer->priv_virt = NULL;
> + mutex_init(&buffer->lock);
> + buffer->vmap_cnt = 0;
> + buffer->vaddr = NULL;
> + buffer->pagecount = 0;
> + buffer->pages = NULL;
> + INIT_LIST_HEAD(&buffer->attachments);
> + buffer->free = free;
> +}
> +
> +struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
> + int fd_flags)
> +{
> + DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> + exp_info.ops = &heap_helper_ops;
> + exp_info.size = buffer->size;
> + exp_info.flags = fd_flags;
> + exp_info.priv = buffer;
> +
> + return dma_buf_export(&exp_info);
> +}
> +
> +static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer)
> +{
> + void *vaddr;
> +
> + vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
> + if (!vaddr)
> + return ERR_PTR(-ENOMEM);
> +
> + return vaddr;
> +}
> +
> +static void dma_heap_buffer_destroy(struct heap_helper_buffer *buffer)
> +{
> + if (buffer->vmap_cnt > 0) {
> + WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
> + vunmap(buffer->vaddr);
> + }
> +
> + buffer->free(buffer);
> +}
> +
> +static void *dma_heap_buffer_vmap_get(struct heap_helper_buffer *buffer)
> +{
> + void *vaddr;
> +
> + if (buffer->vmap_cnt) {
> + buffer->vmap_cnt++;
> + return buffer->vaddr;
> + }
> + vaddr = dma_heap_map_kernel(buffer);
> + if (IS_ERR(vaddr))
> + return vaddr;
> + buffer->vaddr = vaddr;
> + buffer->vmap_cnt++;
> + return vaddr;
> +}
> +
> +static void dma_heap_buffer_vmap_put(struct heap_helper_buffer *buffer)
> +{
> + if (!--buffer->vmap_cnt) {
nit: just checking here cause I don't know the order in which vmap_get() and
vmap_put() is expected to be called from dmabuf, the manual refcounting
based map/unmap is ok?
I know ion had this for a while and it worked fine over the years, but I
don't know if anybody saw any issues with it.
> + vunmap(buffer->vaddr);
> + buffer->vaddr = NULL;
> + }
> +}
> +
> +struct dma_heaps_attachment {
> + struct device *dev;
> + struct sg_table table;
> + struct list_head list;
> +};
> +
> +static int dma_heap_attach(struct dma_buf *dmabuf,
> + struct dma_buf_attachment *attachment)
> +{
> + struct dma_heaps_attachment *a;
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> + int ret;
> +
> + a = kzalloc(sizeof(*a), GFP_KERNEL);
> + if (!a)
> + return -ENOMEM;
> +
> + ret = sg_alloc_table_from_pages(&a->table, buffer->pages,
> + buffer->pagecount, 0,
> + buffer->pagecount << PAGE_SHIFT,
> + GFP_KERNEL);
> + if (ret) {
> + kfree(a);
> + return ret;
> + }
> +
> + a->dev = attachment->dev;
> + INIT_LIST_HEAD(&a->list);
> +
> + attachment->priv = a;
> +
> + mutex_lock(&buffer->lock);
> + list_add(&a->list, &buffer->attachments);
> + mutex_unlock(&buffer->lock);
> +
> + return 0;
> +}
> +
> +static void dma_heap_detach(struct dma_buf *dmabuf,
> + struct dma_buf_attachment *attachment)
> +{
> + struct dma_heaps_attachment *a = attachment->priv;
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> +
> + mutex_lock(&buffer->lock);
> + list_del(&a->list);
> + mutex_unlock(&buffer->lock);
> +
> + sg_free_table(&a->table);
> + kfree(a);
> +}
> +
> +static
> +struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment,
> + enum dma_data_direction direction)
> +{
> + struct dma_heaps_attachment *a = attachment->priv;
> + struct sg_table *table;
> +
> + table = &a->table;
> +
> + if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
> + direction))
> + table = ERR_PTR(-ENOMEM);
> + return table;
> +}
> +
> +static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
> + struct sg_table *table,
> + enum dma_data_direction direction)
> +{
> + dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
> +}
> +
> +static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf)
> +{
> + struct vm_area_struct *vma = vmf->vma;
> + struct heap_helper_buffer *buffer = vma->vm_private_data;
> +
> + if (vmf->pgoff > buffer->pagecount)
> + return VM_FAULT_SIGBUS;
> +
> + vmf->page = buffer->pages[vmf->pgoff];
> + get_page(vmf->page);
> +
> + return 0;
> +}
> +
> +static const struct vm_operations_struct dma_heap_vm_ops = {
> + .fault = dma_heap_vm_fault,
> +};
> +
> +static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
> +{
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> +
> + if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
> + return -EINVAL;
> +
> + vma->vm_ops = &dma_heap_vm_ops;
> + vma->vm_private_data = buffer;
> +
> + return 0;
> +}
> +
> +static void dma_heap_dma_buf_release(struct dma_buf *dmabuf)
> +{
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> +
> + dma_heap_buffer_destroy(buffer);
> +}
> +
> +static int dma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
> + enum dma_data_direction direction)
> +{
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> + struct dma_heaps_attachment *a;
> + int ret = 0;
> +
> + mutex_lock(&buffer->lock);
> +
> + if (buffer->vmap_cnt)
> + invalidate_kernel_vmap_range(buffer->vaddr, buffer->size);
> +
> + list_for_each_entry(a, &buffer->attachments, list) {
> + dma_sync_sg_for_cpu(a->dev, a->table.sgl, a->table.nents,
> + direction);
> + }
> + mutex_unlock(&buffer->lock);
> +
> + return ret;
> +}
> +
> +static int dma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
> + enum dma_data_direction direction)
> +{
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> + struct dma_heaps_attachment *a;
> +
> + mutex_lock(&buffer->lock);
> +
> + if (buffer->vmap_cnt)
> + flush_kernel_vmap_range(buffer->vaddr, buffer->size);
> +
> + list_for_each_entry(a, &buffer->attachments, list) {
> + dma_sync_sg_for_device(a->dev, a->table.sgl, a->table.nents,
> + direction);
> + }
> + mutex_unlock(&buffer->lock);
> +
> + return 0;
> +}
> +
> +static void *dma_heap_dma_buf_vmap(struct dma_buf *dmabuf)
> +{
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> + void *vaddr;
> +
> + mutex_lock(&buffer->lock);
> + vaddr = dma_heap_buffer_vmap_get(buffer);
> + mutex_unlock(&buffer->lock);
> +
> + return vaddr;
> +}
> +
> +static void dma_heap_dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
> +{
> + struct heap_helper_buffer *buffer = dmabuf->priv;
> +
> + mutex_lock(&buffer->lock);
> + dma_heap_buffer_vmap_put(buffer);
> + mutex_unlock(&buffer->lock);
> +}
> +
> +const struct dma_buf_ops heap_helper_ops = {
> + .map_dma_buf = dma_heap_map_dma_buf,
> + .unmap_dma_buf = dma_heap_unmap_dma_buf,
> + .mmap = dma_heap_mmap,
> + .release = dma_heap_dma_buf_release,
> + .attach = dma_heap_attach,
> + .detach = dma_heap_detach,
> + .begin_cpu_access = dma_heap_dma_buf_begin_cpu_access,
> + .end_cpu_access = dma_heap_dma_buf_end_cpu_access,
> + .vmap = dma_heap_dma_buf_vmap,
> + .vunmap = dma_heap_dma_buf_vunmap,
> +};
> diff --git a/drivers/dma-buf/heaps/heap-helpers.h b/drivers/dma-buf/heaps/heap-helpers.h
> new file mode 100644
> index 000000000000..911c931f7f06
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/heap-helpers.h
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * DMABUF Heaps helper code
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +
> +#ifndef _HEAP_HELPERS_H
> +#define _HEAP_HELPERS_H
> +
> +#include <linux/dma-heap.h>
> +#include <linux/list.h>
> +
> +/**
> + * struct heap_helper_buffer - helper buffer metadata
> + * @heap: back pointer to the heap the buffer came from
> + * @dmabuf: backing dma-buf for this buffer
> + * @size: size of the buffer
> + * @flags: buffer specific flags
nit: Are thee dmabuf flags, or dmabuf_heap specific / allocation related flags?
> + * @priv_virt pointer to heap specific private value
nit: text looks misaligned (or is it my editor?)
> + * @lock mutext to protect the data in this structure
> + * @vmap_cnt count of vmap references on the buffer
> + * @vaddr vmap'ed virtual address
> + * @pagecount number of pages in the buffer
> + * @pages list of page pointers
> + * @attachments list of device attachments
ditto
> + *
> + * @free heap callback to free the buffer
> + */
> +struct heap_helper_buffer {
/bikeshed/
s/heap_helper_buffer/dma_heap_buffer ?
The "heap helper buffer" doesn't really convey what it is.
> + struct dma_heap *heap;
> + struct dma_buf *dmabuf;
> + size_t size;
> + unsigned long flags;
> +
> + void *priv_virt;
> + struct mutex lock;
> + int vmap_cnt;
> + void *vaddr;
> + pgoff_t pagecount;
> + struct page **pages;
> + struct list_head attachments;
> +
> + void (*free)(struct heap_helper_buffer *buffer);
> +};
> +
> +void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
> + void (*free)(struct heap_helper_buffer *));
> +
> +struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
> + int fd_flags);
> +
> +extern const struct dma_buf_ops heap_helper_ops;
> +#endif /* _HEAP_HELPERS_H */
> --
> 2.17.1
>
On Fri, Nov 01, 2019 at 09:42:36PM +0000, John Stultz wrote:
> This patch adds system heap to the dma-buf heaps framework.
>
> This allows applications to get a page-allocator backed dma-buf
> for non-contiguous memory.
>
> This code is an evolution of the Android ION implementation, so
> thanks to its original authors and maintainters:
> Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
>
> Cc: Laura Abbott <[email protected]>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
> Reviewed-by: Benjamin Gaignard <[email protected]>
> Reviewed-by: Brian Starkey <[email protected]>
> Acked-by: Laura Abbott <[email protected]>
> Tested-by: Ayan Kumar Halder <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
Acked-by: Sandeep Patil <[email protected]>
On Fri, Nov 01, 2019 at 09:42:38PM +0000, John Stultz wrote:
> Add very trivial allocation and import test for dma-heaps,
> utilizing the vgem driver as a test importer.
>
> A good chunk of this code taken from:
> tools/testing/selftests/android/ion/ionmap_test.c
> Originally by Laura Abbott <[email protected]>
>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
> Reviewed-by: Benjamin Gaignard <[email protected]>
> Reviewed-by: Brian Starkey <[email protected]>
> Acked-by: Laura Abbott <[email protected]>
> Tested-by: Ayan Kumar Halder <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
> ---
> v2:
> * Switched to use reworked dma-heap apis
> v3:
> * Add simple mmap
> * Utilize dma-buf testdev to test importing
> v4:
> * Rework to use vgem
> * Pass in fd_flags to match interface changes
> * Skip . and .. dirs
> v6:
> * Number of style/cleanups suggested by Brian
> v7:
> * Whitespace fixup for checkpatch
> v8:
> * More checkpatch whitespace fixups
> v9:
> * Better handling error returns out to main, suggested
> by Brian Starkey
> * Switch to using snprintf, suggested by Brian
> v14:
> * Fix a missing return value
> * Add calls to test the GET_FEATURES ioctl
> * Build fix reported by kernel test robot <[email protected]>
> and fixed by Xiao Yang <[email protected]>
> * Minor Makefile cleanups
> ---
> tools/testing/selftests/dmabuf-heaps/Makefile | 6 +
> .../selftests/dmabuf-heaps/dmabuf-heap.c | 255 ++++++++++++++++++
> 2 files changed, 261 insertions(+)
> create mode 100644 tools/testing/selftests/dmabuf-heaps/Makefile
> create mode 100644 tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
>
> diff --git a/tools/testing/selftests/dmabuf-heaps/Makefile b/tools/testing/selftests/dmabuf-heaps/Makefile
> new file mode 100644
> index 000000000000..607c2acd2082
> --- /dev/null
> +++ b/tools/testing/selftests/dmabuf-heaps/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0
> +CFLAGS += -static -O3 -Wl,-no-as-needed -Wall -I../../../../usr/include
> +
> +TEST_GEN_PROGS = dmabuf-heap
> +
> +include ../lib.mk
> diff --git a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
> new file mode 100644
> index 000000000000..ec47901ef2e2
> --- /dev/null
> +++ b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
> @@ -0,0 +1,255 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <dirent.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +#include <sys/types.h>
> +
> +#include <linux/dma-buf.h>
> +#include <drm/drm.h>
> +
> +#include "../../../../include/uapi/linux/dma-heap.h"
> +
> +#define DEVPATH "/dev/dma_heap"
> +
> +static int check_vgem(int fd)
> +{
> + drm_version_t version = { 0 };
> + char name[5];
> + int ret;
> +
> + version.name_len = 4;
> + version.name = name;
> +
> + ret = ioctl(fd, DRM_IOCTL_VERSION, &version);
> + if (ret)
> + return 0;
> +
> + return !strcmp(name, "vgem");
> +}
> +
> +static int open_vgem(void)
> +{
> + int i, fd;
> + const char *drmstr = "/dev/dri/card";
> +
> + fd = -1;
> + for (i = 0; i < 16; i++) {
> + char name[80];
> +
> + snprintf(name, 80, "%s%u", drmstr, i);
> +
> + fd = open(name, O_RDWR);
> + if (fd < 0)
> + continue;
> +
> + if (!check_vgem(fd)) {
> + close(fd);
> + fd = -1;
> + continue;
> + } else {
> + break;
> + }
> + }
> + return fd;
> +}
> +
> +static int import_vgem_fd(int vgem_fd, int dma_buf_fd, uint32_t *handle)
> +{
> + struct drm_prime_handle import_handle = {
> + .fd = dma_buf_fd,
> + .flags = 0,
> + .handle = 0,
> + };
> + int ret;
> +
> + ret = ioctl(vgem_fd, DRM_IOCTL_PRIME_FD_TO_HANDLE, &import_handle);
> + if (ret == 0)
> + *handle = import_handle.handle;
> + return ret;
> +}
> +
> +static void close_handle(int vgem_fd, uint32_t handle)
> +{
> + struct drm_gem_close close = {
> + .handle = handle,
> + };
> +
> + ioctl(vgem_fd, DRM_IOCTL_GEM_CLOSE, &close);
> +}
> +
> +static int dmabuf_heap_open(char *name)
> +{
> + int ret, fd;
> + char buf[256];
> +
> + ret = snprintf(buf, 256, "%s/%s", DEVPATH, name);
> + if (ret < 0) {
> + printf("snprintf failed!\n");
> + return ret;
> + }
> +
> + fd = open(buf, O_RDWR);
> + if (fd < 0)
> + printf("open %s failed!\n", buf);
> + return fd;
> +}
> +
> +static int dmabuf_heap_get_features(int fd, unsigned long long *features)
> +{
> + struct dma_heap_get_features_data data = {0};
I'm curious if the test continues to work if you don't zero initialize here?
(See my comment in patch 1/5)
Acked-by: Sandeep Patil <[email protected]>
On Fri, Nov 01, 2019 at 09:42:37PM +0000, John Stultz wrote:
> This adds a CMA heap, which allows userspace to allocate
> a dma-buf of contiguous memory out of a CMA region.
>
> This code is an evolution of the Android ION implementation, so
> thanks to its original author and maintainters:
> Benjamin Gaignard, Laura Abbott, and others!
>
> NOTE: This patch only adds the default CMA heap. We will enable
> selectively adding other CMA memory regions to the dmabuf heaps
> interface with a later patch (which requires a dt binding)
>
> Cc: Laura Abbott <[email protected]>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
> Reviewed-by: Benjamin Gaignard <[email protected]>
> Reviewed-by: Brian Starkey <[email protected]>
> Acked-by: Laura Abbott <[email protected]>
> Tested-by: Ayan Kumar Halder <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
Acked-by: Sandeep Patil <[email protected]>
On Fri, 1 Nov 2019 21:42:33 +0000
John Stultz <[email protected]> wrote:
> This again? I know!
>
> Apologies to all who hoped I'd stop bothering them with this
> patch set, but I ran afoul of the DRM tree rules by not
> getting the userland patches properly reviewed prior to the
> patches landing (I mistakenly was waiting for the patches to
> land upstream before pushing the userland patches). Thus,
> these were correctly reverted from the drm-misc-next tree.
Hi John,
mind, you have to get userland patches reviewed and accepted but *not
pushed*.
You cannot push/merge userland patches before the kernel patches have
properly landed, that bit you got right. But the supposedly confusing
bit is that for kernel patches to land, the userspace patches must be
reviewed and accepted first.
I just wanted to clarify this since you wrote "before pushing the
userland patches" above.
Thanks,
pq
>
> My attempts to quickly fix the userland review issue didn't get
> very far, as the revert brought additional eyes to the patchset,
> and further interface changes were requested (comically, which
> is the exact reason I was waiting to push the userland changes
> :)
>
> So like groundhog day, here we are again, with v14:
>
> This patchset implements per-heap devices which can be opened
> directly and then an ioctl is used to allocate a dmabuf from the
> heap.
>
> The interface is similar, but much simpler then IONs, only
> providing an ALLOC ioctl (and a GET_FEATURES interface to help
> with any future changes to the interface).
>
> Also, I've provided relatively simple system and cma heaps.
>
> I've booted and tested these patches with AOSP on the HiKey960
> using the kernel tree here:
> https://git.linaro.org/people/john.stultz/android-dev.git/log/?h=dev/dma-buf-heap
>
> And the userspace changes here:
> https://android-review.googlesource.com/c/device/linaro/hikey/+/909436
>
> Compared to ION, this patchset is missing the system-contig,
> carveout and chunk heaps, as I don't have a device that uses
> those, so I'm unable to do much useful validation there.
> Additionally we have no upstream users of chunk or carveout,
> and the system-contig has been deprecated in the common/andoid-*
> kernels, so this should be ok.
>
> I've also removed the stats accounting, since any such
> accounting should be implemented by dma-buf core or the heaps
> themselves.
>
> New in v14:
> * Reworked ioctl handler to zero fill any difference in
> structure size, similar to what the DRM core does, as
> suggested by Dave Airlie
> * Removed now unnecessary reserved bits in allocate_data
> * Added get_features ioctl as suggested by Dave Airlie
> * Removed pr_warn_once messages as requested by Dave
> Airlie
> * Fix missing argment to WARN() in dma_heap_buffer_destroy()
> found and fixed by Dan Carpenter <[email protected]>
> * Add check in fault hanlder that pgoff isn't larger then
> pagecount, reported by Dan Carpenter
> * Fix "redundant assignment to variable ret" issue reported
> by Colin King and fixed by Andrew Davis
> * Fix a missing return value in kselftest
> * Add calls to test the GET_FEATURES ioctl in ksefltest
> * Build fix reported by kernel test robot <[email protected]>
> and fixed by Xiao Yang <[email protected]> for kselftest
> * Minor kselftest Makefile cleanups
>
> Many thanks again to the folks above who found and submitted
> fixes to small issues while the patches were in -next! I've
> folded them in to the patch set here.
>
> The ioctl rework to avoid reserved fields, was mostly duplicated
> from the DRM core, but it does add some complexity to the ioctl
> handler so I'd appreciate extra review.
>
> It felt substantial enough that I've removed the previous reviewed
> by and acked-by tags, but please let me know if you'd like me to
> re-add yours back.
>
> Apologies again for my flub and the extra noise here!
> I really appreciate everyone's patience with with me.
>
> thanks
> -john
>
>
> Cc: Laura Abbott <[email protected]>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
>
> Andrew F. Davis (1):
> dma-buf: Add dma-buf heaps framework
>
> John Stultz (4):
> dma-buf: heaps: Add heap helpers
> dma-buf: heaps: Add system heap to dmabuf heaps
> dma-buf: heaps: Add CMA heap to dmabuf heaps
> kselftests: Add dma-heap test
>
> MAINTAINERS | 18 +
> drivers/dma-buf/Kconfig | 11 +
> drivers/dma-buf/Makefile | 2 +
> drivers/dma-buf/dma-heap.c | 313 ++++++++++++++++++
> drivers/dma-buf/heaps/Kconfig | 14 +
> drivers/dma-buf/heaps/Makefile | 4 +
> drivers/dma-buf/heaps/cma_heap.c | 178 ++++++++++
> drivers/dma-buf/heaps/heap-helpers.c | 271 +++++++++++++++
> drivers/dma-buf/heaps/heap-helpers.h | 55 +++
> drivers/dma-buf/heaps/system_heap.c | 124 +++++++
> include/linux/dma-heap.h | 59 ++++
> include/uapi/linux/dma-heap.h | 77 +++++
> tools/testing/selftests/dmabuf-heaps/Makefile | 6 +
> .../selftests/dmabuf-heaps/dmabuf-heap.c | 255 ++++++++++++++
> 14 files changed, 1387 insertions(+)
> create mode 100644 drivers/dma-buf/dma-heap.c
> create mode 100644 drivers/dma-buf/heaps/Kconfig
> create mode 100644 drivers/dma-buf/heaps/Makefile
> create mode 100644 drivers/dma-buf/heaps/cma_heap.c
> create mode 100644 drivers/dma-buf/heaps/heap-helpers.c
> create mode 100644 drivers/dma-buf/heaps/heap-helpers.h
> create mode 100644 drivers/dma-buf/heaps/system_heap.c
> create mode 100644 include/linux/dma-heap.h
> create mode 100644 include/uapi/linux/dma-heap.h
> create mode 100644 tools/testing/selftests/dmabuf-heaps/Makefile
> create mode 100644 tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
>
Hi John,
On Fri, Nov 01, 2019 at 09:42:34PM +0000, John Stultz wrote:
> From: "Andrew F. Davis" <[email protected]>
>
> This framework allows a unified userspace interface for dma-buf
> exporters, allowing userland to allocate specific types of memory
> for use in dma-buf sharing.
>
> Each heap is given its own device node, which a user can allocate
> a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.
>
> Additionally should the interface grow in the future, we have a
> DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
> flags.
The userspace patch doesn't use this - and there's no indication of
what it's intended to allow in the future. I missed the discussion
about it, do you have a link?
I thought the preferred approach was to add the new ioctl only when we
need it, and new userspace on old kernels will get "ENOSYS" to know
that the kernel doesn't support it.
>
> This code is an evoluiton of the Android ION implementation,
> and a big thanks is due to its authors/maintainers over time
> for their effort:
> Rebecca Schultz Zavin, Colin Cross, Benjamin Gaignard,
> Laura Abbott, and many other contributors!
>
> Cc: Laura Abbott <[email protected]>
> Cc: Benjamin Gaignard <[email protected]>
> Cc: Sumit Semwal <[email protected]>
> Cc: Liam Mark <[email protected]>
> Cc: Pratik Patel <[email protected]>
> Cc: Brian Starkey <[email protected]>
> Cc: Vincent Donnefort <[email protected]>
> Cc: Sudipto Paul <[email protected]>
> Cc: Andrew F. Davis <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Chenbo Feng <[email protected]>
> Cc: Alistair Strachan <[email protected]>
> Cc: Hridya Valsaraju <[email protected]>
> Cc: Sandeep Patil <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: [email protected]
> Signed-off-by: Andrew F. Davis <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
> ---
> v2:
> * Folded down fixes I had previously shared in implementing
> heaps
> * Make flags a u64 (Suggested by Laura)
> * Add PAGE_ALIGN() fix to the core alloc funciton
> * IOCTL fixups suggested by Brian
> * Added fixes suggested by Benjamin
> * Removed core stats mgmt, as that should be implemented by
> per-heap code
> * Changed alloc to return a dma-buf fd, rather than a buffer
> (as it simplifies error handling)
> v3:
> * Removed scare-quotes in MAINTAINERS email address
> * Get rid of .release function as it didn't do anything (from
> Christoph)
> * Renamed filp to file (suggested by Christoph)
> * Split out ioctl handling to separate function (suggested by
> Christoph)
> * Add comment documenting PAGE_ALIGN usage (suggested by Brian)
> * Switch from idr to Xarray (suggested by Brian)
> * Fixup cdev creation (suggested by Brian)
> * Avoid EXPORT_SYMBOL until we finalize modules (suggested by
> Brian)
> * Make struct dma_heap internal only (folded in from Andrew)
> * Small cleanups suggested by GregKH
> * Provide class->devnode callback to get consistent /dev/
> subdirectory naming (Suggested by Bjorn)
> v4:
> * Folded down dma-heap.h change that was in a following patch
> * Added fd_flags entry to allocation structure and pass it
> through to heap code for use on dma-buf fd creation (suggested
> by Benjamin)
> v5:
> * Minor cleanups
> v6:
> * Improved error path handling, minor whitespace fixes, both
> suggested by Brian
> v7:
> * Longer Kconfig description to quiet checkpatch warnings
> * Re-add compat_ioctl bits (Hridya noticed 32bit userland wasn't
> working)
> v8:
> * Make struct dma_heap_ops consts (Suggested by Christoph)
> * Checkpatch whitespace fixups
> v9:
> * Minor cleanups suggested by Brian Starkey
> * Rename dma_heap_get_data->dma_heap_get_drvdata suggested
> by Hilf Danton
> v11:
> * Kconfig text improvements suggested by Randy Dunlap
> v12:
> * Add logic to prevent duplicately named heaps being added
> * Add symbol exports for heaps as modules
> v13:
> * Re-remove symbol exports per discussion w/ Brian. Will
> resubmit in a separte patch for review
> v14:
> * Reworked ioctl handler to zero fill any difference in
> structure size, similar to what the DRM core does, as
> suggested by Dave Airlie
> * Removed now unnecessary reserved bits in allocate_data
> * Added get_features ioctl as suggested by Dave Airlie
> * Removed pr_warn_once messages as requested by Dave
> Airlie
> ---
> MAINTAINERS | 18 ++
> drivers/dma-buf/Kconfig | 9 +
> drivers/dma-buf/Makefile | 1 +
> drivers/dma-buf/dma-heap.c | 313 ++++++++++++++++++++++++++++++++++
> include/linux/dma-heap.h | 59 +++++++
> include/uapi/linux/dma-heap.h | 77 +++++++++
> 6 files changed, 477 insertions(+)
> create mode 100644 drivers/dma-buf/dma-heap.c
> create mode 100644 include/linux/dma-heap.h
> create mode 100644 include/uapi/linux/dma-heap.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c6c34d04ce95..77c3e993fb2f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4940,6 +4940,24 @@ F: include/linux/*fence.h
> F: Documentation/driver-api/dma-buf.rst
> T: git git://anongit.freedesktop.org/drm/drm-misc
>
> +DMA-BUF HEAPS FRAMEWORK
> +M: Sumit Semwal <[email protected]>
> +R: Andrew F. Davis <[email protected]>
> +R: Benjamin Gaignard <[email protected]>
> +R: Liam Mark <[email protected]>
> +R: Laura Abbott <[email protected]>
> +R: Brian Starkey <[email protected]>
> +R: John Stultz <[email protected]>
> +S: Maintained
> +L: [email protected]
> +L: [email protected]
> +L: [email protected] (moderated for non-subscribers)
> +F: include/uapi/linux/dma-heap.h
> +F: include/linux/dma-heap.h
> +F: drivers/dma-buf/dma-heap.c
> +F: drivers/dma-buf/heaps/*
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +
> DMA GENERIC OFFLOAD ENGINE SUBSYSTEM
> M: Vinod Koul <[email protected]>
> L: [email protected]
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index a23b6752d11a..bffa58fc3e6e 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -44,4 +44,13 @@ config DMABUF_SELFTESTS
> default n
> depends on DMA_SHARED_BUFFER
>
> +menuconfig DMABUF_HEAPS
> + bool "DMA-BUF Userland Memory Heaps"
> + select DMA_SHARED_BUFFER
> + help
> + Choose this option to enable the DMA-BUF userland memory heaps.
> + This options creates per heap chardevs in /dev/dma_heap/ which
> + allows userspace to allocate dma-bufs that can be shared
> + between drivers.
> +
> endmenu
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> index 03479da06422..caee5eb3d351 100644
> --- a/drivers/dma-buf/Makefile
> +++ b/drivers/dma-buf/Makefile
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
> obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
> dma-resv.o seqno-fence.o
> +obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
> obj-$(CONFIG_SYNC_FILE) += sync_file.o
> obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
> obj-$(CONFIG_UDMABUF) += udmabuf.o
> diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
> new file mode 100644
> index 000000000000..7cdd7179e5fa
> --- /dev/null
> +++ b/drivers/dma-buf/dma-heap.c
> @@ -0,0 +1,313 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Framework for userspace DMA-BUF allocations
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +
> +#include <linux/cdev.h>
> +#include <linux/debugfs.h>
> +#include <linux/device.h>
> +#include <linux/dma-buf.h>
> +#include <linux/err.h>
> +#include <linux/xarray.h>
> +#include <linux/list.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +#include <linux/syscalls.h>
> +#include <linux/dma-heap.h>
> +#include <uapi/linux/dma-heap.h>
> +
> +#define DEVNAME "dma_heap"
> +
> +#define NUM_HEAP_MINORS 128
> +
> +/**
> + * struct dma_heap - represents a dmabuf heap in the system
> + * @name: used for debugging/device-node name
> + * @ops: ops struct for this heap
> + * @minor minor number of this heap device
> + * @heap_devt heap device node
> + * @heap_cdev heap char device
> + *
> + * Represents a heap of memory from which buffers can be made.
> + */
> +struct dma_heap {
> + const char *name;
> + const struct dma_heap_ops *ops;
> + void *priv;
> + unsigned int minor;
> + dev_t heap_devt;
> + struct list_head list;
> + struct cdev heap_cdev;
> +};
> +
> +static LIST_HEAD(heap_list);
> +static DEFINE_MUTEX(heap_list_lock);
> +static dev_t dma_heap_devt;
> +static struct class *dma_heap_class;
> +static DEFINE_XARRAY_ALLOC(dma_heap_minors);
> +
> +static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
> + unsigned int fd_flags,
> + unsigned int heap_flags)
> +{
> + /*
> + * Allocations from all heaps have to begin
> + * and end on page boundaries.
> + */
> + len = PAGE_ALIGN(len);
> + if (!len)
> + return -EINVAL;
> +
> + return heap->ops->allocate(heap, len, fd_flags, heap_flags);
> +}
> +
> +static int dma_heap_open(struct inode *inode, struct file *file)
> +{
> + struct dma_heap *heap;
> +
> + heap = xa_load(&dma_heap_minors, iminor(inode));
> + if (!heap) {
> + pr_err("dma_heap: minor %d unknown.\n", iminor(inode));
> + return -ENODEV;
> + }
> +
> + /* instance data as context */
> + file->private_data = heap;
> + nonseekable_open(inode, file);
> +
> + return 0;
> +}
> +
> +static long dma_heap_ioctl_get_features(struct file *file, void *data)
> +{
> + struct dma_heap_get_features_data *heap_features = data;
> +
> + /* nothing should be passed in */
> + if (heap_features->features)
> + return -EINVAL;
> +
> + heap_features->features = DMA_HEAP_SUPPORTED_FEATURES;
> + return 0;
> +}
> +
> +static long dma_heap_ioctl_allocate(struct file *file, void *data)
> +{
> + struct dma_heap_allocation_data *heap_allocation = data;
> + struct dma_heap *heap = file->private_data;
> + int fd;
> +
> + if (heap_allocation->fd)
> + return -EINVAL;
> +
> + if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
> + return -EINVAL;
> +
> + if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
> + return -EINVAL;
> +
> + fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
> + heap_allocation->fd_flags,
> + heap_allocation->heap_flags);
> + if (fd < 0)
> + return fd;
> +
> + heap_allocation->fd = fd;
> +
> + return 0;
> +}
> +
> +unsigned int dma_heap_ioctl_cmds[] = {
> + DMA_HEAP_IOC_GET_FEATURES,
> + DMA_HEAP_IOC_ALLOC,
> +};
> +
> +static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
> + unsigned long arg)
> +{
> + char stack_kdata[128];
> + char *kdata = stack_kdata;
> + unsigned int kcmd;
> + unsigned int in_size, out_size, drv_size, ksize;
> + int nr = _IOC_NR(ucmd);
> + int ret = 0;
> +
> + if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds))
> + return -EINVAL;
> +
> + /* Get the kernel ioctl cmd that matches */
> + kcmd = dma_heap_ioctl_cmds[nr];
> +
> + /* Figure out the delta between user cmd size and kernel cmd size */
> + drv_size = _IOC_SIZE(kcmd);
> + out_size = _IOC_SIZE(ucmd);
> + in_size = out_size;
> + if ((ucmd & kcmd & IOC_IN) == 0)
> + in_size = 0;
> + if ((ucmd & kcmd & IOC_OUT) == 0)
> + out_size = 0;
> + ksize = max(max(in_size, out_size), drv_size);
> +
> + /* If necessary, allocate buffer for ioctl argument */
> + if (ksize > sizeof(stack_kdata)) {
> + kdata = kmalloc(ksize, GFP_KERNEL);
> + if (!kdata)
> + return -ENOMEM;
> + }
> +
> + if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
> + ret = -EFAULT;
> + goto err;
> + }
> +
> + /* zero out any difference between the kernel/user structure size */
> + if (ksize > in_size)
> + memset(kdata + in_size, 0, ksize - in_size);
> +
> + switch (kcmd) {
> + case DMA_HEAP_IOC_GET_FEATURES:
> + ret = dma_heap_ioctl_get_features(file, kdata);
> + break;
> + case DMA_HEAP_IOC_ALLOC:
> + ret = dma_heap_ioctl_allocate(file, kdata);
> + break;
> + default:
> + return -ENOTTY;
> + }
> +
> + if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
> + ret = -EFAULT;
> +err:
> + if (kdata != stack_kdata)
> + kfree(kdata);
> + return ret;
> +}
The new zeroing stuff all looks good to me - so wrt. that you can add
back my r-b; would still like to get some clarification on the
get_features, though.
Couple of typos below.
> +
> +static const struct file_operations dma_heap_fops = {
> + .owner = THIS_MODULE,
> + .open = dma_heap_open,
> + .unlocked_ioctl = dma_heap_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = dma_heap_ioctl,
> +#endif
> +};
> +
> +/**
> + * dma_heap_get_drvdata() - get per-subdriver data for the heap
> + * @heap: DMA-Heap to retrieve private data for
> + *
> + * Returns:
> + * The per-subdriver data for the heap.
> + */
> +void *dma_heap_get_drvdata(struct dma_heap *heap)
> +{
> + return heap->priv;
> +}
> +
> +struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
> +{
> + struct dma_heap *heap, *h, *err_ret;
> + struct device *dev_ret;
> + int ret;
> +
> + if (!exp_info->name || !strcmp(exp_info->name, "")) {
> + pr_err("dma_heap: Cannot add heap without a name\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (!exp_info->ops || !exp_info->ops->allocate) {
> + pr_err("dma_heap: Cannot add heap with invalid ops struct\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + /* check the name is unique */
> + mutex_lock(&heap_list_lock);
> + list_for_each_entry(h, &heap_list, list) {
> + if (!strcmp(h->name, exp_info->name)) {
> + mutex_unlock(&heap_list_lock);
> + pr_err("dma_heap: Already registered heap named %s\n",
> + exp_info->name);
> + return ERR_PTR(-EINVAL);
> + }
> + }
> + mutex_unlock(&heap_list_lock);
> +
> + heap = kzalloc(sizeof(*heap), GFP_KERNEL);
> + if (!heap)
> + return ERR_PTR(-ENOMEM);
> +
> + heap->name = exp_info->name;
> + heap->ops = exp_info->ops;
> + heap->priv = exp_info->priv;
> +
> + /* Find unused minor number */
> + ret = xa_alloc(&dma_heap_minors, &heap->minor, heap,
> + XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL);
> + if (ret < 0) {
> + pr_err("dma_heap: Unable to get minor number for heap\n");
> + err_ret = ERR_PTR(ret);
> + goto err0;
> + }
> +
> + /* Create device */
> + heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor);
> +
> + cdev_init(&heap->heap_cdev, &dma_heap_fops);
> + ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1);
> + if (ret < 0) {
> + pr_err("dma_heap: Unable to add char device\n");
> + err_ret = ERR_PTR(ret);
> + goto err1;
> + }
> +
> + dev_ret = device_create(dma_heap_class,
> + NULL,
> + heap->heap_devt,
> + NULL,
> + heap->name);
> + if (IS_ERR(dev_ret)) {
> + pr_err("dma_heap: Unable to create device\n");
> + err_ret = ERR_CAST(dev_ret);
> + goto err2;
> + }
> + /* Add heap to the list */
> + mutex_lock(&heap_list_lock);
> + list_add(&heap->list, &heap_list);
> + mutex_unlock(&heap_list_lock);
> +
> + return heap;
> +
> +err2:
> + cdev_del(&heap->heap_cdev);
> +err1:
> + xa_erase(&dma_heap_minors, heap->minor);
> +err0:
> + kfree(heap);
> + return err_ret;
> +}
> +
> +static char *dma_heap_devnode(struct device *dev, umode_t *mode)
> +{
> + return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev));
> +}
> +
> +static int dma_heap_init(void)
> +{
> + int ret;
> +
> + ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
> + if (ret)
> + return ret;
> +
> + dma_heap_class = class_create(THIS_MODULE, DEVNAME);
> + if (IS_ERR(dma_heap_class)) {
> + unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
> + return PTR_ERR(dma_heap_class);
> + }
> + dma_heap_class->devnode = dma_heap_devnode;
> +
> + return 0;
> +}
> +subsys_initcall(dma_heap_init);
> diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
> new file mode 100644
> index 000000000000..454e354d1ffb
> --- /dev/null
> +++ b/include/linux/dma-heap.h
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * DMABUF Heaps Allocation Infrastructure
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +
> +#ifndef _DMA_HEAPS_H
> +#define _DMA_HEAPS_H
> +
> +#include <linux/cdev.h>
> +#include <linux/types.h>
> +
> +struct dma_heap;
> +
> +/**
> + * struct dma_heap_ops - ops to operate on a given heap
> + * @allocate: allocate dmabuf and return fd
> + *
> + * allocate returns dmabuf fd on success, -errno on error.
> + */
> +struct dma_heap_ops {
> + int (*allocate)(struct dma_heap *heap,
> + unsigned long len,
> + unsigned long fd_flags,
> + unsigned long heap_flags);
> +};
> +
> +/**
> + * struct dma_heap_export_info - information needed to export a new dmabuf heap
> + * @name: used for debugging/device-node name
> + * @ops: ops struct for this heap
> + * @priv: heap exporter private data
> + *
> + * Information needed to export a new dmabuf heap.
> + */
> +struct dma_heap_export_info {
> + const char *name;
> + const struct dma_heap_ops *ops;
> + void *priv;
> +};
> +
> +/**
> + * dma_heap_get_drvdata() - get per-heap driver data
> + * @heap: DMA-Heap to retrieve private data for
> + *
> + * Returns:
> + * The per-heap data for the heap.
> + */
> +void *dma_heap_get_drvdata(struct dma_heap *heap);
> +
> +/**
> + * dma_heap_add - adds a heap to dmabuf heaps
> + * @exp_info: information needed to register this heap
> + */
> +struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
> +
> +#endif /* _DMA_HEAPS_H */
> diff --git a/include/uapi/linux/dma-heap.h b/include/uapi/linux/dma-heap.h
> new file mode 100644
> index 000000000000..22f620991758
> --- /dev/null
> +++ b/include/uapi/linux/dma-heap.h
> @@ -0,0 +1,77 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * DMABUF Heaps Userspace API
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +#ifndef _UAPI_LINUX_DMABUF_POOL_H
> +#define _UAPI_LINUX_DMABUF_POOL_H
> +
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +/**
> + * DOC: DMABUF Heaps Userspace API
> + */
> +
> +#define DMA_HEAP_FEATURE_NONE (0x0)
> +
> +/* Currrently no supported features */
> +#define DMA_HEAP_SUPPORTED_FEATURES (DMA_HEAP_FEATURE_NONE)
> +
> +/**
> + * struct dma_heap_get_features_data - metadata passed from userspace for
> + * getting interface features
> + * @features: features flag returned from kernel
> + *
> + * Provided by userspace as an argument to the ioctl
> + */
> +struct dma_heap_get_features_data {
> + __u64 features;
> +};
> +
> +/* Valid FD_FLAGS are O_CLOEXEC, O_RDONLY, O_WRONLY, O_RDWR */
> +#define DMA_HEAP_VALID_FD_FLAGS (O_CLOEXEC | O_ACCMODE)
> +
> +/* Currently no heap flags */
> +#define DMA_HEAP_VALID_HEAP_FLAGS (0)
> +
> +/**
> + * struct dma_heap_allocation_data - metadata passed from userspace for
> + * allocations
> + * @len: size of the allocation
> + * @fd: will be populated with a fd which provdes the
> + * handle to the allocated dma-buf
> + * @fd_flags: file descriptor flags used when allocating
> + * @heap_flags: flags passed to heap
> + *
> + * Provided by userspace as an argument to the ioctl
> + */
> +struct dma_heap_allocation_data {
> + __u64 len;
> + __u32 fd;
> + __u32 fd_flags;
> + __u64 heap_flags;
> +};
> +
> +#define DMA_HEAP_IOC_MAGIC 'H'
> +
> +/**
> + * DOC: DMA_HEAP_IOC_GET_FEATURES - Get interface features
> + *
> + * Takes an dma_heap_features_data struct and returns it with the features
> + * flages set with the interfaces supported features.
> + */
s/Takes an/Takes a/
s/features flages/feature flags/
s/interfaces/interface's/
> +#define DMA_HEAP_IOC_GET_FEATURES _IOR(DMA_HEAP_IOC_MAGIC, 0x0,\
> + struct dma_heap_get_features_data)
> +/**
> + * DOC: DMA_HEAP_IOC_ALLOC - allocate memory from pool
> + *
> + * Takes an dma_heap_allocation_data struct and returns it with the fd field
> + * populated with the dmabuf handle of the allocation.
> + */
> +#define DMA_HEAP_IOC_ALLOC _IOWR(DMA_HEAP_IOC_MAGIC, 0x1,\
s/Takes an/Takes a/
Thanks!
-Brian
> + struct dma_heap_allocation_data)
> +
> +#endif /* _UAPI_LINUX_DMABUF_POOL_H */
> --
> 2.17.1
>
On Mon, 4 Nov 2019 at 20:24, Brian Starkey <[email protected]> wrote:
>
> Hi John,
>
> On Fri, Nov 01, 2019 at 09:42:34PM +0000, John Stultz wrote:
> > From: "Andrew F. Davis" <[email protected]>
> >
> > This framework allows a unified userspace interface for dma-buf
> > exporters, allowing userland to allocate specific types of memory
> > for use in dma-buf sharing.
> >
> > Each heap is given its own device node, which a user can allocate
> > a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.
> >
> > Additionally should the interface grow in the future, we have a
> > DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
> > flags.
>
> The userspace patch doesn't use this - and there's no indication of
> what it's intended to allow in the future. I missed the discussion
> about it, do you have a link?
>
> I thought the preferred approach was to add the new ioctl only when we
> need it, and new userspace on old kernels will get "ENOSYS" to know
> that the kernel doesn't support it.
This works once, expand the interface 3 or 4 times with no features
ioctl, and you start being hostile to userspace, which feature does
ENOSYS mean isn't supported etc.
Next userspace starts to rely on kernel version, but then someone
backports a feature, down the rabbit hole we go.
Be nice to userspace give them a features ioctl they can use to figure
out in advance which of the 4 uapis the kernel supports.
Dave.
Hi Dave,
On Tue, Nov 05, 2019 at 02:58:17AM +1000, Dave Airlie wrote:
> On Mon, 4 Nov 2019 at 20:24, Brian Starkey <[email protected]> wrote:
> >
> > Hi John,
> >
> > On Fri, Nov 01, 2019 at 09:42:34PM +0000, John Stultz wrote:
> > > From: "Andrew F. Davis" <[email protected]>
> > >
> > > This framework allows a unified userspace interface for dma-buf
> > > exporters, allowing userland to allocate specific types of memory
> > > for use in dma-buf sharing.
> > >
> > > Each heap is given its own device node, which a user can allocate
> > > a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.
> > >
> > > Additionally should the interface grow in the future, we have a
> > > DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
> > > flags.
> >
> > The userspace patch doesn't use this - and there's no indication of
> > what it's intended to allow in the future. I missed the discussion
> > about it, do you have a link?
> >
> > I thought the preferred approach was to add the new ioctl only when we
> > need it, and new userspace on old kernels will get "ENOSYS" to know
> > that the kernel doesn't support it.
>
> This works once, expand the interface 3 or 4 times with no features
> ioctl, and you start being hostile to userspace, which feature does
> ENOSYS mean isn't supported etc.
Sorry, perhaps I wasn't clear (or I misunderstand what you're saying
about working only once). I'm not against adding a get_features ioctl,
I just don't see why we'd add it before we have any features?
When we gain the first "feature", can't we add the get_features ioctl
then? For Future SW that knows about Future features, "ENOSYS" will
always mean "no features". If it doesn't get ENOSYS, then it can use
the ioctl to find out what features it has.
Otherwise we're adding an ioctl which doesn't do anything, based on
the assumption that in the future it _will_ do something... but we
don't know that that is yet... but we're pretty sure whatever it will
do can be described with a u64?
Why not wait until we know what we want it for, and then implement it
with an interface which we know is appropriate at that time?
>
> Next userspace starts to rely on kernel version, but then someone
> backports a feature, down the rabbit hole we go.
>
I suppose that adding the feature ioctl later would mean that it might
be possible to backport a feature without also backporting the ioctl,
depending on how the patches are split up. I think it would be pretty
hard to do accidentally though.
Thanks,
-Brian
> Be nice to userspace give them a features ioctl they can use to figure
> out in advance which of the 4 uapis the kernel supports.
>
> Dave.
On Mon, Nov 04, 2019 at 05:43:51PM +0000, Brian Starkey wrote:
> Hi Dave,
>
> On Tue, Nov 05, 2019 at 02:58:17AM +1000, Dave Airlie wrote:
> > On Mon, 4 Nov 2019 at 20:24, Brian Starkey <[email protected]> wrote:
> > >
> > > Hi John,
> > >
> > > On Fri, Nov 01, 2019 at 09:42:34PM +0000, John Stultz wrote:
> > > > From: "Andrew F. Davis" <[email protected]>
> > > >
> > > > This framework allows a unified userspace interface for dma-buf
> > > > exporters, allowing userland to allocate specific types of memory
> > > > for use in dma-buf sharing.
> > > >
> > > > Each heap is given its own device node, which a user can allocate
> > > > a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.
> > > >
> > > > Additionally should the interface grow in the future, we have a
> > > > DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
> > > > flags.
> > >
> > > The userspace patch doesn't use this - and there's no indication of
> > > what it's intended to allow in the future. I missed the discussion
> > > about it, do you have a link?
> > >
> > > I thought the preferred approach was to add the new ioctl only when we
> > > need it, and new userspace on old kernels will get "ENOSYS" to know
> > > that the kernel doesn't support it.
> >
> > This works once, expand the interface 3 or 4 times with no features
> > ioctl, and you start being hostile to userspace, which feature does
> > ENOSYS mean isn't supported etc.
>
> Sorry, perhaps I wasn't clear (or I misunderstand what you're saying
> about working only once). I'm not against adding a get_features ioctl,
> I just don't see why we'd add it before we have any features?
>
> When we gain the first "feature", can't we add the get_features ioctl
> then? For Future SW that knows about Future features, "ENOSYS" will
> always mean "no features". If it doesn't get ENOSYS, then it can use
> the ioctl to find out what features it has.
>
> Otherwise we're adding an ioctl which doesn't do anything, based on
> the assumption that in the future it _will_ do something... but we
> don't know that that is yet... but we're pretty sure whatever it will
> do can be described with a u64?
>
> Why not wait until we know what we want it for, and then implement it
> with an interface which we know is appropriate at that time?
Yeah I'm with Brian, adding the get_feature ioctl when we need it.
Otherwise it's going to be broken somehow and we'll immediately ref to
get_features2 :-)
-Daniel
> > Next userspace starts to rely on kernel version, but then someone
> > backports a feature, down the rabbit hole we go.
> >
>
> I suppose that adding the feature ioctl later would mean that it might
> be possible to backport a feature without also backporting the ioctl,
> depending on how the patches are split up. I think it would be pretty
> hard to do accidentally though.
>
> Thanks,
> -Brian
>
> > Be nice to userspace give them a features ioctl they can use to figure
> > out in advance which of the 4 uapis the kernel supports.
> >
> > Dave.
>
> _______________________________________________
> dri-devel mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
On Sun, Nov 3, 2019 at 8:02 AM <[email protected]> wrote:
> > +static long dma_heap_ioctl_get_features(struct file *file, void *data)
> > +{
> > + struct dma_heap_get_features_data *heap_features = data;
> > +
> > + /* nothing should be passed in */
> > + if (heap_features->features)
> > + return -EINVAL;
>
> curious, what are we trying to protect here? Unless I misunderstood this, you
> are forcing userspace to 0 initialize the structure passed into the ioctl.
> So an uninitialized stack variable passed into ioctl() will end up returning
> -EINVAL .. I am not sure thats ok?
Yea, so the rational mostly comes from the document here:
https://www.kernel.org/doc/Documentation/ioctl/botching-up-ioctls.rst
The general idea is to be very conservative in what you accept on
IOCTLs to avoid any extensions made from breaking existing userland.
Usually this is most critical for write-ioctls, and probably isn't as
important for read ones like get_features, but I don't see much
downside to enforcing it.
> Plus, the point is pointing into the kmalloc'ed memory or the local 'char
> stack_data[128] from the ioctl() function, so not sure if this check was
> intentional? If so, may be easier to 0 initialize *kdata in the ioctl
> function below?
So the bits in the kdata (be it kmalloced or on the stack) is all
copied over from the userpointer. So we're just trying to enforce that
userland zeros it before passing it in.
Thanks again for your other feedback, I'll address them in the next revision!
thanks
-john
On Mon, Nov 4, 2019 at 2:24 AM Brian Starkey <[email protected]> wrote:
> On Fri, Nov 01, 2019 at 09:42:34PM +0000, John Stultz wrote:
> > From: "Andrew F. Davis" <[email protected]>
> >
> > Additionally should the interface grow in the future, we have a
> > DMA_HEAP_IOC_GET_FEATURES ioctl which can return future feature
> > flags.
>
> The userspace patch doesn't use this - and there's no indication of
> what it's intended to allow in the future. I missed the discussion
> about it, do you have a link?
Yea. Sorry, It was feedback I got via IRC. If your curious the irc log
can be found here:
https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&highlight_names=&date=2019-10-30&show_html=true
> The new zeroing stuff all looks good to me - so wrt. that you can add
> back my r-b; would still like to get some clarification on the
> get_features, though.
From Daniel's feedback it sounds like I'll drop the empty get_features
ioctl then.
> Couple of typos below.
Apologies for my bad spelling! Thanks for the continued attention and review!
-john
On Mon, Nov 4, 2019 at 12:18 AM Pekka Paalanen <[email protected]> wrote:
> On Fri, 1 Nov 2019 21:42:33 +0000
> John Stultz <[email protected]> wrote:
>
> > This again? I know!
> >
> > Apologies to all who hoped I'd stop bothering them with this
> > patch set, but I ran afoul of the DRM tree rules by not
> > getting the userland patches properly reviewed prior to the
> > patches landing (I mistakenly was waiting for the patches to
> > land upstream before pushing the userland patches). Thus,
> > these were correctly reverted from the drm-misc-next tree.
>
> Hi John,
>
> mind, you have to get userland patches reviewed and accepted but *not
> pushed*.
>
> You cannot push/merge userland patches before the kernel patches have
> properly landed, that bit you got right. But the supposedly confusing
> bit is that for kernel patches to land, the userspace patches must be
> reviewed and accepted first.
>
> I just wanted to clarify this since you wrote "before pushing the
> userland patches" above.
Yea. Sorry, "pushed" isn't a very clear term. In AOSP, one must push a
patch to Gerrit before it is reviewed.
However, once something is reviewed it usually is merged immediately
(pending automated precommit testing).
So I tend to use the term "pushed for review" as submitting patches
for review as ready to be merged. In this case, technically I had
actually "pushed" the changes to Gerrit, but hadn't added anyone to
review, to ensure the patches were not' accidentally reviewed and
merged.
But If you look at the Gerrit log now, you'll see I've added reviewers
and provided a note explicitly to not merge the changes.
So apologies for the confusion. I do believe I understand the
requirement now, and am doing my best to adhere to them.
That said, given different userland projects use different approaches,
I do find it a little strange on the insistence that userland patches
cannot be merged to their project before the kernel changes land.
Obviously no interface is final and any userland that does so has some
risk that it will change and break, but there are many cases where
distros support new features in their userland not yet merged
upstream. Ensuring there is a real opensource user for the kernel
feature is important, but I'm not sure I understand why the kernel is
dictating rules as to how userspace merges code.
thanks
-john
On Sun, Nov 3, 2019 at 8:13 AM <[email protected]> wrote:
> On Fri, Nov 01, 2019 at 09:42:35PM +0000, John Stultz wrote:
> > Add generic helper dmabuf ops for dma heaps, so we can reduce
> > the amount of duplicative code for the exported dmabufs.
> >
> > This code is an evolution of the Android ION implementation, so
> > thanks to its original authors and maintainters:
> > Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
> >
> > Cc: Laura Abbott <[email protected]>
> > Cc: Benjamin Gaignard <[email protected]>
> > Cc: Sumit Semwal <[email protected]>
> > Cc: Liam Mark <[email protected]>
> > Cc: Pratik Patel <[email protected]>
> > Cc: Brian Starkey <[email protected]>
> > Cc: Vincent Donnefort <[email protected]>
> > Cc: Sudipto Paul <[email protected]>
> > Cc: Andrew F. Davis <[email protected]>
> > Cc: Christoph Hellwig <[email protected]>
> > Cc: Chenbo Feng <[email protected]>
> > Cc: Alistair Strachan <[email protected]>
> > Cc: Hridya Valsaraju <[email protected]>
> > Cc: Sandeep Patil <[email protected]>
> > Cc: Hillf Danton <[email protected]>
> > Cc: Dave Airlie <[email protected]>
> > Cc: [email protected]
> > Reviewed-by: Benjamin Gaignard <[email protected]>
> > Reviewed-by: Brian Starkey <[email protected]>
> > Acked-by: Laura Abbott <[email protected]>
> > Tested-by: Ayan Kumar Halder <[email protected]>
> > Signed-off-by: John Stultz <[email protected]>
>
> I have one question and a naming suggestin below (sorry).
>
> Acked-by: Sandeep Patil <[email protected]>
> > +
> > +static void dma_heap_buffer_vmap_put(struct heap_helper_buffer *buffer)
> > +{
> > + if (!--buffer->vmap_cnt) {
>
> nit: just checking here cause I don't know the order in which vmap_get() and
> vmap_put() is expected to be called from dmabuf, the manual refcounting
> based map/unmap is ok?
>
> I know ion had this for a while and it worked fine over the years, but I
> don't know if anybody saw any issues with it.
> > + vunmap(buffer->vaddr);
> > + buffer->vaddr = NULL;
> > + }
> > +}
> > +
> > +#ifndef _HEAP_HELPERS_H
> > +#define _HEAP_HELPERS_H
> > +
> > +#include <linux/dma-heap.h>
> > +#include <linux/list.h>
> > +
> > +/**
> > + * struct heap_helper_buffer - helper buffer metadata
> > + * @heap: back pointer to the heap the buffer came from
> > + * @dmabuf: backing dma-buf for this buffer
> > + * @size: size of the buffer
> > + * @flags: buffer specific flags
> nit: Are thee dmabuf flags, or dmabuf_heap specific / allocation related flags?
Good point. They were going to be for the generic flags but as there's
no supported flags yet, there's no reason to track that in the helper
code.
I'll drop it
> > + * @priv_virt pointer to heap specific private value
> nit: text looks misaligned (or is it my editor?)
Looks ok to me in vim.
> > + * @lock mutext to protect the data in this structure
> > + * @vmap_cnt count of vmap references on the buffer
> > + * @vaddr vmap'ed virtual address
> > + * @pagecount number of pages in the buffer
> > + * @pages list of page pointers
> > + * @attachments list of device attachments
> ditto
> > + *
> > + * @free heap callback to free the buffer
> > + */
> > +struct heap_helper_buffer {
> /bikeshed/
> s/heap_helper_buffer/dma_heap_buffer ?
>
> The "heap helper buffer" doesn't really convey what it is.
So its the helper structure that is used with all the helper
functions. Since other dmabuf heaps don't have to use the helper
infrastructure, they wouldn't need this structure, so I don't want to
name it too generically to confuse folks.
thanks
-john
On Mon, Nov 4, 2019 at 11:34 AM John Stultz <[email protected]> wrote:
>
> On Sun, Nov 3, 2019 at 8:13 AM <[email protected]> wrote:
> > On Fri, Nov 01, 2019 at 09:42:35PM +0000, John Stultz wrote:
> > > Add generic helper dmabuf ops for dma heaps, so we can reduce
> > > the amount of duplicative code for the exported dmabufs.
> > >
> > > This code is an evolution of the Android ION implementation, so
> > > thanks to its original authors and maintainters:
> > > Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
> > >
> > > Cc: Laura Abbott <[email protected]>
> > > Cc: Benjamin Gaignard <[email protected]>
> > > Cc: Sumit Semwal <[email protected]>
> > > Cc: Liam Mark <[email protected]>
> > > Cc: Pratik Patel <[email protected]>
> > > Cc: Brian Starkey <[email protected]>
> > > Cc: Vincent Donnefort <[email protected]>
> > > Cc: Sudipto Paul <[email protected]>
> > > Cc: Andrew F. Davis <[email protected]>
> > > Cc: Christoph Hellwig <[email protected]>
> > > Cc: Chenbo Feng <[email protected]>
> > > Cc: Alistair Strachan <[email protected]>
> > > Cc: Hridya Valsaraju <[email protected]>
> > > Cc: Sandeep Patil <[email protected]>
> > > Cc: Hillf Danton <[email protected]>
> > > Cc: Dave Airlie <[email protected]>
> > > Cc: [email protected]
> > > Reviewed-by: Benjamin Gaignard <[email protected]>
> > > Reviewed-by: Brian Starkey <[email protected]>
> > > Acked-by: Laura Abbott <[email protected]>
> > > Tested-by: Ayan Kumar Halder <[email protected]>
> > > Signed-off-by: John Stultz <[email protected]>
> >
> > I have one question and a naming suggestin below (sorry).
> >
> > Acked-by: Sandeep Patil <[email protected]>
>
> > > +
> > > +static void dma_heap_buffer_vmap_put(struct heap_helper_buffer *buffer)
> > > +{
> > > + if (!--buffer->vmap_cnt) {
> >
> > nit: just checking here cause I don't know the order in which vmap_get() and
> > vmap_put() is expected to be called from dmabuf, the manual refcounting
> > based map/unmap is ok?
> >
> > I know ion had this for a while and it worked fine over the years, but I
> > don't know if anybody saw any issues with it.
Sorry, I hit send before replying to this bit. I'll double check on this.
thanks again for the review!
-john
On Mon, 4 Nov 2019 11:21:21 -0800
John Stultz <[email protected]> wrote:
> So apologies for the confusion. I do believe I understand the
> requirement now, and am doing my best to adhere to them.
Hi John,
that's cool, the kernel regression rules are so strict that any slip in
userspace projects can seriously hamper kernel work, so I'm kind of on
the edge now that I've realized that.
> That said, given different userland projects use different approaches,
> I do find it a little strange on the insistence that userland patches
> cannot be merged to their project before the kernel changes land.
> Obviously no interface is final and any userland that does so has some
> risk that it will change and break, but there are many cases where
> distros support new features in their userland not yet merged
> upstream. Ensuring there is a real opensource user for the kernel
> feature is important, but I'm not sure I understand why the kernel is
> dictating rules as to how userspace merges code.
My own understanding is that if a userspace project manages to release
a version that uses new kernel UAPI which was not finalized yet, then
when kernel people fix something in the UAPI and attempt to land it,
the difference will make the userspace now break because the feature
does not work like it used to. The userspace project is already
released and in the wild, so it cannot be retroactively fixed.
According to the kernel rules, any kernel change that breaks existing
userspace, no matter how wrong userspace was, is the kernel's fault. So
that means the kernel developers cannot land the new fixed feature, but
will need to figure out a way to expose the new feature without
triggering the new path in the userspace project that jumped the gun.
Often the breakage is not found out immediately but after a kernel
release. That means the already released feature will have to be
reverted, and then figure out how to re-introduce it so that it does
not trigger the userspace project that jumped the gun. This obviously
affects also userspace projects that wanted to use the feature and did
not jump the gun - they do not break, they just do not find the feature
anymore and need to be fixed.
In my opinion, saying "do not merge" to userspace projects is better
than "do not release" until the UAPI is finalized in the kernel.
I'm not sure it even matters if the userspace project makes a release
or not. All it takes is for someone to grab a snapshot and distribute
it, and for someone to complain.
Thanks,
pq