by Brian Starkey

[permalink] [raw]

Subject: Re: [PATCH v5 5/5] kselftests: Add dma-heap test

Hi John,

I haven't looked at any selftests before, but is there any advantage
to using the test harness?
https://www.kernel.org/doc/html/v5.1/dev-tools/kselftest.html#test-harness

Couple of minor things below

On Fri, Jun 07, 2019 at 03:07:19AM +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: [email protected]
> Reviewed-by: Benjamin Gaignard <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
> Change-Id: Ib98569fdda6378eb086b8092fb5d6bd419b8d431
> ---
> 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
> ---
> tools/testing/selftests/dmabuf-heaps/Makefile | 11 +
> .../selftests/dmabuf-heaps/dmabuf-heap.c | 232 ++++++++++++++++++
> 2 files changed, 243 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..c414ad36b4bf
> --- /dev/null
> +++ b/tools/testing/selftests/dmabuf-heaps/Makefile
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: GPL-2.0
> +CFLAGS += -static -O3 -Wl,-no-as-needed -Wall
> +#LDLIBS += -lrt -lpthread -lm
> +
> +# these are all "safe" tests that don't modify
> +# system time or require escalated privileges
> +TEST_GEN_PROGS = dmabuf-heap
> +

newline

> +
> +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..33d4b105c673
> --- /dev/null
> +++ b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
> @@ -0,0 +1,232 @@
> +// 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"
> +
> +int check_vgem(int fd)

Functions can be static

> +{
> + 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 1;
> +
> + return strcmp(name, "vgem");
> +}
> +
> +int open_vgem(void)
> +{
> + int i, fd;
> + const char *drmstr = "/dev/dri/card";
> +
> + fd = -1;
> + for (i = 0; i < 16; i++) {
> + char name[80];
> +
> + sprintf(name, "%s%u", drmstr, i);
> +
> + fd = open(name, O_RDWR);
> + if (fd < 0)
> + continue;
> +
> + if (check_vgem(fd)) {

It's a minor thing, but the naming vs the logic reads backwards to me
here. I'd expect check_vgem() to return true for vgem.

> + close(fd);
> + continue;
> + } else {
> + break;
> + }
> +
> + }
> + return fd;
> +}
> +
> +int import_vgem_fd(int vgem_fd, int dma_buf_fd, uint32_t *handle)
> +{
> + struct drm_prime_handle import_handle = { 0 };
> + int ret;
> +
> + import_handle.fd = dma_buf_fd;
> + import_handle.flags = 0;
> + import_handle.handle = 0;

You could just initialise import_handle directly. Same for the other
functions

> +
> + ret = ioctl(vgem_fd, DRM_IOCTL_PRIME_FD_TO_HANDLE, &import_handle);
> + if (ret == 0)
> + *handle = import_handle.handle;
> + return ret;
> +}
> +
> +void close_handle(int vgem_fd, uint32_t handle)
> +{
> + struct drm_gem_close close = { 0 };
> +
> + close.handle = handle;
> + ioctl(vgem_fd, DRM_IOCTL_GEM_CLOSE, &close);
> +}
> +
> +
> +int dmabuf_heap_open(char *name)
> +{
> + int ret, fd;
> + char buf[256];
> +
> + ret = sprintf(buf, "%s/%s", DEVPATH, name);
> + if (ret < 0) {
> + printf("sprintf failed!\n");
> + return ret;
> + }
> +
> + fd = open(buf, O_RDWR);
> + if (fd < 0)
> + printf("open %s failed!\n", buf);
> + return fd;
> +}
> +
> +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,
> + };

Like this :-)

> + int ret;
> +
> + if (dmabuf_fd == NULL)
> + return -EINVAL;
> +
> + ret = ioctl(fd, DMA_HEAP_IOC_ALLOC, &data);
> + if (ret < 0)
> + return ret;
> + *dmabuf_fd = (int)data.fd;
> + return ret;
> +}
> +
> +void dmabuf_sync(int fd, int start_stop)
> +{
> + struct dma_buf_sync sync = { 0 };
> + int ret;
> +
> + sync.flags = start_stop | DMA_BUF_SYNC_RW;
> + ret = ioctl(fd, DMA_BUF_IOCTL_SYNC, &sync);
> + if (ret)
> + printf("sync failed %d\n", errno);
> +

newline

> +}
> +
> +#define ONE_MEG (1024*1024)
> +
> +void do_test(char *heap_name)
> +{
> + int heap_fd = -1, dmabuf_fd = -1, importer_fd = -1;
> + uint32_t handle = 0;
> + void *p = NULL;
> + int ret;
> +
> + printf("Testing heap: %s\n", heap_name);
> +
> + heap_fd = dmabuf_heap_open(heap_name);
> + if (heap_fd < 0)
> + return;
> +
> + printf("Allocating 1 MEG\n");
> + ret = dmabuf_heap_alloc(heap_fd, ONE_MEG, 0, &dmabuf_fd);
> + if (ret)

It'd be good to print something here so you can easily tell if
allocations are failing.

> + 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");
> + 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);

Are the selftests using the kernel coding style? If so, there's some
spaces missing.

> + 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;

No need for this

> +
> +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);
> +}
> +
> +
> +int main(void)
> +{
> + DIR *d;
> + struct dirent *dir;
> +
> + 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;
> +
> + do_test(dir->d_name);
> + }
> +

I know it's only a test, and you're about to exit, but you should
probably still closedir() in case someone copies this code.

Cheers,
-Brian

> + return 0;
> +}
> --
> 2.17.1
>