This patchset makes dma-buf exporters responisble for taking care of
the reservation lock. I also included patch that moves drm-shmem to use
reservation lock, to let CI test the whole set. I'm going to take all
the patches via the drm-misc tree, please give an ack.
Previous policy stated that dma-buf core takes the lock around mmap()
callback. Which meant that both importers and exporters shouldn't touch
the reservation lock in the mmap() code path. This worked well until
Intel-CI found a deadlock problem in a case of self-imported dma-buf [1].
The problem happens when userpace mmaps a self-imported dma-buf, i.e.
mmaps the dma-buf FD. DRM core treats self-imported dma-bufs as own GEMs
[2]. There is no way to differentiate a prime GEM from a normal GEM for
drm-shmem in drm_gem_shmem_mmap(), which resulted in a deadlock problem
for drm-shmem mmap() code path once it's switched to use reservation lock.
It was difficult to fix the drm-shmem problem without adjusting dma-buf
locking policy. In parctice not much changed from importers perspective
because previosly dma-buf was taking the lock in between of importers
and exporters. Now this lock is shifted down to exporters.
[1] https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_114671v2/shard-snb5/igt@prime_vgem@[email protected]
[2] https://elixir.bootlin.com/linux/v6.3-rc4/source/drivers/gpu/drm/drm_prime.c#L924
Changelog:
v2: - Added ack from Christian König to the DRM patch.
- Dropped "fixes" tag from the patches, like was requested by
Christian König. The patches don't actually need a backport
and merely improve the locking policy.
- Dropped "reverts" from the patch titles to prevent them from
auto-backporting by the stable bot based on the title.
- Added r-b from Emil Velikov and placed the drm_WARN in the
drm-shmem patch like he suggested in a comment to v1.
- Corrected drm-shmem patch dma_resv_lock(obj->resv) inconsistently
used with dma_resv_unlock(shmem->base.resv). Now shmem->base.resv
variant is used for all locks/unlocks.
Dmitry Osipenko (7):
media: videobuf2: Don't assert held reservation lock for dma-buf
mmapping
dma-buf/heaps: Don't assert held reservation lock for dma-buf mmapping
udmabuf: Don't assert held reservation lock for dma-buf mmapping
fastrpc: Don't assert held reservation lock for dma-buf mmapping
drm: Don't assert held reservation lock for dma-buf mmapping
dma-buf: Change locking policy for mmap()
drm/shmem-helper: Switch to reservation lock
drivers/dma-buf/dma-buf.c | 17 +-
drivers/dma-buf/heaps/cma_heap.c | 3 -
drivers/dma-buf/heaps/system_heap.c | 3 -
drivers/dma-buf/udmabuf.c | 2 -
drivers/gpu/drm/drm_gem_shmem_helper.c | 208 ++++++++----------
drivers/gpu/drm/drm_prime.c | 2 -
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 -
drivers/gpu/drm/lima/lima_gem.c | 8 +-
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 2 -
drivers/gpu/drm/panfrost/panfrost_drv.c | 7 +-
.../gpu/drm/panfrost/panfrost_gem_shrinker.c | 6 +-
drivers/gpu/drm/panfrost/panfrost_mmu.c | 19 +-
drivers/gpu/drm/tegra/gem.c | 2 -
.../common/videobuf2/videobuf2-dma-contig.c | 3 -
.../media/common/videobuf2/videobuf2-dma-sg.c | 3 -
.../common/videobuf2/videobuf2-vmalloc.c | 3 -
drivers/misc/fastrpc.c | 3 -
include/drm/drm_gem_shmem_helper.h | 14 +-
18 files changed, 117 insertions(+), 190 deletions(-)
--
2.39.2
Don't assert held dma-buf reservation lock on memory mapping of exported
buffer.
We're going to change dma-buf mmap() locking policy such that exporters
will have to handle the lock. The previous locking policy caused deadlock
problem for DRM drivers in a case of self-imported dma-bufs once these
drivers are moved to use reservation lock universally. The problem is
solved by moving the lock down to exporters. This patch prepares videobuf2
for the locking policy update.
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/media/common/videobuf2/videobuf2-dma-contig.c | 3 ---
drivers/media/common/videobuf2/videobuf2-dma-sg.c | 3 ---
drivers/media/common/videobuf2/videobuf2-vmalloc.c | 3 ---
3 files changed, 9 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 205d3cac425c..2fa455d4a048 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -11,7 +11,6 @@
*/
#include <linux/dma-buf.h>
-#include <linux/dma-resv.h>
#include <linux/module.h>
#include <linux/refcount.h>
#include <linux/scatterlist.h>
@@ -456,8 +455,6 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct iosys_map *map)
static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
struct vm_area_struct *vma)
{
- dma_resv_assert_held(dbuf->resv);
-
return vb2_dc_mmap(dbuf->priv, vma);
}
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index 183037fb1273..28f3fdfe23a2 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -10,7 +10,6 @@
* the Free Software Foundation.
*/
-#include <linux/dma-resv.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/refcount.h>
@@ -498,8 +497,6 @@ static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf,
static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
struct vm_area_struct *vma)
{
- dma_resv_assert_held(dbuf->resv);
-
return vb2_dma_sg_mmap(dbuf->priv, vma);
}
diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
index a6c6d2fcaaa4..7c635e292106 100644
--- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
+++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
@@ -10,7 +10,6 @@
* the Free Software Foundation.
*/
-#include <linux/dma-resv.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mm.h>
@@ -319,8 +318,6 @@ static int vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf,
static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
struct vm_area_struct *vma)
{
- dma_resv_assert_held(dbuf->resv);
-
return vb2_vmalloc_mmap(dbuf->priv, vma);
}
--
2.39.2
Don't assert held dma-buf reservation lock on memory mapping of exported
buffer.
We're going to change dma-buf mmap() locking policy such that exporters
will have to handle the lock. The previous locking policy caused deadlock
problem for DRM drivers in a case of self-imported dma-bufs once these
drivers are moved to use reservation lock universally. The problem is
solved by moving the lock down to exporters. This patch prepares udmabuf
for the locking policy update.
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/udmabuf.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 740d6e426ee9..277f1afa9552 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -52,8 +52,6 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
{
struct udmabuf *ubuf = buf->priv;
- dma_resv_assert_held(buf->resv);
-
if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
return -EINVAL;
--
2.39.2
Don't assert held dma-buf reservation lock on memory mapping of exported
buffer.
We're going to change dma-buf mmap() locking policy such that exporters
will have to handle the lock. The previous locking policy caused deadlock
problem for DRM drivers in a case of self-imported dma-bufs once these
drivers are moved to use reservation lock universally. The problem is
solved by moving the lock down to exporters. This patch prepares fastrpc
for the locking policy update.
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/misc/fastrpc.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index a701132638cf..7e9c9ad37fd9 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -6,7 +6,6 @@
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
-#include <linux/dma-resv.h>
#include <linux/idr.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
@@ -733,8 +732,6 @@ static int fastrpc_mmap(struct dma_buf *dmabuf,
struct fastrpc_buf *buf = dmabuf->priv;
size_t size = vma->vm_end - vma->vm_start;
- dma_resv_assert_held(dmabuf->resv);
-
return dma_mmap_coherent(buf->dev, vma, buf->virt,
FASTRPC_PHYS(buf->phys), size);
}
--
2.39.2
Don't assert held dma-buf reservation lock on memory mapping of exported
buffer.
We're going to change dma-buf mmap() locking policy such that exporters
will have to handle the lock. The previous locking policy caused deadlock
problem for DRM drivers in a case of self-imported dma-bufs once these
drivers are moved to use reservation lock universally. The problem
solved by moving the lock down to exporters. This patch prepares dma-buf
heaps for the locking policy update.
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/heaps/cma_heap.c | 3 ---
drivers/dma-buf/heaps/system_heap.c | 3 ---
2 files changed, 6 deletions(-)
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index 1131fb943992..28fb04eccdd0 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -13,7 +13,6 @@
#include <linux/dma-buf.h>
#include <linux/dma-heap.h>
#include <linux/dma-map-ops.h>
-#include <linux/dma-resv.h>
#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/io.h>
@@ -183,8 +182,6 @@ static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
{
struct cma_heap_buffer *buffer = dmabuf->priv;
- dma_resv_assert_held(dmabuf->resv);
-
if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
return -EINVAL;
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index e8bd10e60998..fcf836ba9c1f 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -13,7 +13,6 @@
#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
#include <linux/dma-heap.h>
-#include <linux/dma-resv.h>
#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/mm.h>
@@ -202,8 +201,6 @@ static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
struct sg_page_iter piter;
int ret;
- dma_resv_assert_held(dmabuf->resv);
-
for_each_sgtable_page(table, &piter, vma->vm_pgoff) {
struct page *page = sg_page_iter_page(&piter);
--
2.39.2
Change locking policy of mmap() callback, making exporters responsible
for handling dma-buf reservation locking. Previous locking policy stated
that dma-buf is locked for both importers and exporters by the dma-buf
core, which caused a deadlock problem for DRM drivers in a case of
self-imported dma-bufs which required to take the lock from the DRM
exporter side.
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index aa4ea8530cb3..21916bba77d5 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -131,7 +131,6 @@ static struct file_system_type dma_buf_fs_type = {
static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
{
struct dma_buf *dmabuf;
- int ret;
if (!is_dma_buf_file(file))
return -EINVAL;
@@ -147,11 +146,7 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
dmabuf->size >> PAGE_SHIFT)
return -EINVAL;
- dma_resv_lock(dmabuf->resv, NULL);
- ret = dmabuf->ops->mmap(dmabuf, vma);
- dma_resv_unlock(dmabuf->resv);
-
- return ret;
+ return dmabuf->ops->mmap(dmabuf, vma);
}
static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
@@ -850,6 +845,7 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
* - &dma_buf_ops.release()
* - &dma_buf_ops.begin_cpu_access()
* - &dma_buf_ops.end_cpu_access()
+ * - &dma_buf_ops.mmap()
*
* 2. These &dma_buf_ops callbacks are invoked with locked dma-buf
* reservation and exporter can't take the lock:
@@ -858,7 +854,6 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
* - &dma_buf_ops.unpin()
* - &dma_buf_ops.map_dma_buf()
* - &dma_buf_ops.unmap_dma_buf()
- * - &dma_buf_ops.mmap()
* - &dma_buf_ops.vmap()
* - &dma_buf_ops.vunmap()
*
@@ -1463,8 +1458,6 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF);
int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
unsigned long pgoff)
{
- int ret;
-
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;
@@ -1485,11 +1478,7 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
vma_set_file(vma, dmabuf->file);
vma->vm_pgoff = pgoff;
- dma_resv_lock(dmabuf->resv, NULL);
- ret = dmabuf->ops->mmap(dmabuf, vma);
- dma_resv_unlock(dmabuf->resv);
-
- return ret;
+ return dmabuf->ops->mmap(dmabuf, vma);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
--
2.39.2
Don't assert held dma-buf reservation lock on memory mapping of exported
buffer.
We're going to change dma-buf mmap() locking policy such that exporters
will have to handle the lock. The previous locking policy caused deadlock
problem for DRM drivers in a case of self-imported dma-bufs once these
drivers are moved to use reservation lock universally. The problem is
solved by moving the lock down to exporters. This patch prepares DRM
drivers for the locking policy update.
Reviewed-by: Emil Velikov <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/drm_prime.c | 2 --
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 --
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 2 --
drivers/gpu/drm/tegra/gem.c | 2 --
4 files changed, 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 149cd4ff6a3b..cea85e84666f 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -781,8 +781,6 @@ int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
- dma_resv_assert_held(dma_buf->resv);
-
if (!dev->driver->gem_prime_mmap)
return -ENOSYS;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index fd556a076d05..1df74f7aa3dc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -97,8 +97,6 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *
struct drm_i915_private *i915 = to_i915(obj->base.dev);
int ret;
- dma_resv_assert_held(dma_buf->resv);
-
if (obj->base.size < vma->vm_end - vma->vm_start)
return -EINVAL;
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index 3abc47521b2c..8e194dbc9506 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -66,8 +66,6 @@ static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
struct drm_gem_object *obj = buffer->priv;
int ret = 0;
- dma_resv_assert_held(buffer->resv);
-
ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
if (ret < 0)
return ret;
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index bce991a2ccc0..871ef5d26523 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -693,8 +693,6 @@ static int tegra_gem_prime_mmap(struct dma_buf *buf, struct vm_area_struct *vma)
struct drm_gem_object *gem = buf->priv;
int err;
- dma_resv_assert_held(buf->resv);
-
err = drm_gem_mmap_obj(gem, gem->size, vma);
if (err < 0)
return err;
--
2.39.2
Replace all drm-shmem locks with a GEM reservation lock. This makes locks
consistent with dma-buf locking convention where importers are responsible
for holding reservation lock for all operations performed over dma-bufs,
preventing deadlock between dma-buf importers and exporters.
Suggested-by: Daniel Vetter <[email protected]>
Acked-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 208 ++++++++----------
drivers/gpu/drm/lima/lima_gem.c | 8 +-
drivers/gpu/drm/panfrost/panfrost_drv.c | 7 +-
.../gpu/drm/panfrost/panfrost_gem_shrinker.c | 6 +-
drivers/gpu/drm/panfrost/panfrost_mmu.c | 19 +-
include/drm/drm_gem_shmem_helper.h | 14 +-
6 files changed, 114 insertions(+), 148 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 4ea6507a77e5..395942ca36fe 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -88,8 +88,6 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
if (ret)
goto err_release;
- mutex_init(&shmem->pages_lock);
- mutex_init(&shmem->vmap_lock);
INIT_LIST_HEAD(&shmem->madv_list);
if (!private) {
@@ -141,11 +139,13 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
- drm_WARN_ON(obj->dev, shmem->vmap_use_count);
-
if (obj->import_attach) {
drm_prime_gem_destroy(obj, shmem->sgt);
} else {
+ dma_resv_lock(shmem->base.resv, NULL);
+
+ drm_WARN_ON(obj->dev, shmem->vmap_use_count);
+
if (shmem->sgt) {
dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
DMA_BIDIRECTIONAL, 0);
@@ -154,18 +154,18 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
}
if (shmem->pages)
drm_gem_shmem_put_pages(shmem);
- }
- drm_WARN_ON(obj->dev, shmem->pages_use_count);
+ drm_WARN_ON(obj->dev, shmem->pages_use_count);
+
+ dma_resv_unlock(shmem->base.resv);
+ }
drm_gem_object_release(obj);
- mutex_destroy(&shmem->pages_lock);
- mutex_destroy(&shmem->vmap_lock);
kfree(shmem);
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
-static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
+static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
struct page **pages;
@@ -197,35 +197,16 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
}
/*
- * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object
+ * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
* @shmem: shmem GEM object
*
- * This function makes sure that backing pages exists for the shmem GEM object
- * and increases the use count.
- *
- * Returns:
- * 0 on success or a negative error code on failure.
+ * This function decreases the use count and puts the backing pages when use drops to zero.
*/
-int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
+void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
- int ret;
-
- drm_WARN_ON(obj->dev, obj->import_attach);
-
- ret = mutex_lock_interruptible(&shmem->pages_lock);
- if (ret)
- return ret;
- ret = drm_gem_shmem_get_pages_locked(shmem);
- mutex_unlock(&shmem->pages_lock);
-
- return ret;
-}
-EXPORT_SYMBOL(drm_gem_shmem_get_pages);
-static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
-{
- struct drm_gem_object *obj = &shmem->base;
+ dma_resv_assert_held(shmem->base.resv);
if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
return;
@@ -243,20 +224,25 @@ static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
shmem->pages_mark_accessed_on_put);
shmem->pages = NULL;
}
+EXPORT_SYMBOL(drm_gem_shmem_put_pages);
-/*
- * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
- * @shmem: shmem GEM object
- *
- * This function decreases the use count and puts the backing pages when use drops to zero.
- */
-void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
+static int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
+{
+ int ret;
+
+ dma_resv_assert_held(shmem->base.resv);
+
+ ret = drm_gem_shmem_get_pages(shmem);
+
+ return ret;
+}
+
+static void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
{
- mutex_lock(&shmem->pages_lock);
- drm_gem_shmem_put_pages_locked(shmem);
- mutex_unlock(&shmem->pages_lock);
+ dma_resv_assert_held(shmem->base.resv);
+
+ drm_gem_shmem_put_pages(shmem);
}
-EXPORT_SYMBOL(drm_gem_shmem_put_pages);
/**
* drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
@@ -271,10 +257,17 @@ EXPORT_SYMBOL(drm_gem_shmem_put_pages);
int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
+ int ret;
drm_WARN_ON(obj->dev, obj->import_attach);
- return drm_gem_shmem_get_pages(shmem);
+ ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
+ if (ret)
+ return ret;
+ ret = drm_gem_shmem_pin_locked(shmem);
+ dma_resv_unlock(shmem->base.resv);
+
+ return ret;
}
EXPORT_SYMBOL(drm_gem_shmem_pin);
@@ -291,12 +284,29 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
drm_WARN_ON(obj->dev, obj->import_attach);
- drm_gem_shmem_put_pages(shmem);
+ dma_resv_lock(shmem->base.resv, NULL);
+ drm_gem_shmem_unpin_locked(shmem);
+ dma_resv_unlock(shmem->base.resv);
}
EXPORT_SYMBOL(drm_gem_shmem_unpin);
-static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
- struct iosys_map *map)
+/*
+ * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
+ * @shmem: shmem GEM object
+ * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
+ * store.
+ *
+ * This function makes sure that a contiguous kernel virtual address mapping
+ * exists for the buffer backing the shmem GEM object. It hides the differences
+ * between dma-buf imported and natively allocated objects.
+ *
+ * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
+ struct iosys_map *map)
{
struct drm_gem_object *obj = &shmem->base;
int ret = 0;
@@ -312,6 +322,8 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
} else {
pgprot_t prot = PAGE_KERNEL;
+ dma_resv_assert_held(shmem->base.resv);
+
if (shmem->vmap_use_count++ > 0) {
iosys_map_set_vaddr(map, shmem->vaddr);
return 0;
@@ -346,45 +358,30 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
return ret;
}
+EXPORT_SYMBOL(drm_gem_shmem_vmap);
/*
- * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
+ * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
* @shmem: shmem GEM object
- * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
- * store.
- *
- * This function makes sure that a contiguous kernel virtual address mapping
- * exists for the buffer backing the shmem GEM object. It hides the differences
- * between dma-buf imported and natively allocated objects.
+ * @map: Kernel virtual address where the SHMEM GEM object was mapped
*
- * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
+ * This function cleans up a kernel virtual address mapping acquired by
+ * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
+ * zero.
*
- * Returns:
- * 0 on success or a negative error code on failure.
+ * This function hides the differences between dma-buf imported and natively
+ * allocated objects.
*/
-int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
- struct iosys_map *map)
-{
- int ret;
-
- ret = mutex_lock_interruptible(&shmem->vmap_lock);
- if (ret)
- return ret;
- ret = drm_gem_shmem_vmap_locked(shmem, map);
- mutex_unlock(&shmem->vmap_lock);
-
- return ret;
-}
-EXPORT_SYMBOL(drm_gem_shmem_vmap);
-
-static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
- struct iosys_map *map)
+void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
+ struct iosys_map *map)
{
struct drm_gem_object *obj = &shmem->base;
if (obj->import_attach) {
dma_buf_vunmap(obj->import_attach->dmabuf, map);
} else {
+ dma_resv_assert_held(shmem->base.resv);
+
if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))
return;
@@ -397,26 +394,6 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
shmem->vaddr = NULL;
}
-
-/*
- * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
- * @shmem: shmem GEM object
- * @map: Kernel virtual address where the SHMEM GEM object was mapped
- *
- * This function cleans up a kernel virtual address mapping acquired by
- * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
- * zero.
- *
- * This function hides the differences between dma-buf imported and natively
- * allocated objects.
- */
-void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
- struct iosys_map *map)
-{
- mutex_lock(&shmem->vmap_lock);
- drm_gem_shmem_vunmap_locked(shmem, map);
- mutex_unlock(&shmem->vmap_lock);
-}
EXPORT_SYMBOL(drm_gem_shmem_vunmap);
static int
@@ -447,24 +424,24 @@ drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
*/
int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
{
- mutex_lock(&shmem->pages_lock);
+ dma_resv_assert_held(shmem->base.resv);
if (shmem->madv >= 0)
shmem->madv = madv;
madv = shmem->madv;
- mutex_unlock(&shmem->pages_lock);
-
return (madv >= 0);
}
EXPORT_SYMBOL(drm_gem_shmem_madvise);
-void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
+void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
struct drm_device *dev = obj->dev;
+ dma_resv_assert_held(shmem->base.resv);
+
drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem));
dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
@@ -472,7 +449,7 @@ void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
kfree(shmem->sgt);
shmem->sgt = NULL;
- drm_gem_shmem_put_pages_locked(shmem);
+ drm_gem_shmem_put_pages(shmem);
shmem->madv = -1;
@@ -488,17 +465,6 @@ void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
}
-EXPORT_SYMBOL(drm_gem_shmem_purge_locked);
-
-bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
-{
- if (!mutex_trylock(&shmem->pages_lock))
- return false;
- drm_gem_shmem_purge_locked(shmem);
- mutex_unlock(&shmem->pages_lock);
-
- return true;
-}
EXPORT_SYMBOL(drm_gem_shmem_purge);
/**
@@ -551,7 +517,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
/* We don't use vmf->pgoff since that has the fake offset */
page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
- mutex_lock(&shmem->pages_lock);
+ dma_resv_lock(shmem->base.resv, NULL);
if (page_offset >= num_pages ||
drm_WARN_ON_ONCE(obj->dev, !shmem->pages) ||
@@ -563,7 +529,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
}
- mutex_unlock(&shmem->pages_lock);
+ dma_resv_unlock(shmem->base.resv);
return ret;
}
@@ -575,7 +541,7 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
drm_WARN_ON(obj->dev, obj->import_attach);
- mutex_lock(&shmem->pages_lock);
+ dma_resv_lock(shmem->base.resv, NULL);
/*
* We should have already pinned the pages when the buffer was first
@@ -585,7 +551,7 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
shmem->pages_use_count++;
- mutex_unlock(&shmem->pages_lock);
+ dma_resv_unlock(shmem->base.resv);
drm_gem_vm_open(vma);
}
@@ -595,7 +561,10 @@ static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
struct drm_gem_object *obj = vma->vm_private_data;
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+ dma_resv_lock(shmem->base.resv, NULL);
drm_gem_shmem_put_pages(shmem);
+ dma_resv_unlock(shmem->base.resv);
+
drm_gem_vm_close(vma);
}
@@ -633,7 +602,10 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct
return ret;
}
+ dma_resv_lock(shmem->base.resv, NULL);
ret = drm_gem_shmem_get_pages(shmem);
+ dma_resv_unlock(shmem->base.resv);
+
if (ret)
return ret;
@@ -699,7 +671,7 @@ static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_
drm_WARN_ON(obj->dev, obj->import_attach);
- ret = drm_gem_shmem_get_pages_locked(shmem);
+ ret = drm_gem_shmem_get_pages(shmem);
if (ret)
return ERR_PTR(ret);
@@ -721,7 +693,7 @@ static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_
sg_free_table(sgt);
kfree(sgt);
err_put_pages:
- drm_gem_shmem_put_pages_locked(shmem);
+ drm_gem_shmem_put_pages(shmem);
return ERR_PTR(ret);
}
@@ -746,11 +718,11 @@ struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
int ret;
struct sg_table *sgt;
- ret = mutex_lock_interruptible(&shmem->pages_lock);
+ ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
if (ret)
return ERR_PTR(ret);
sgt = drm_gem_shmem_get_pages_sgt_locked(shmem);
- mutex_unlock(&shmem->pages_lock);
+ dma_resv_unlock(shmem->base.resv);
return sgt;
}
diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index 10252dc11a22..4f9736e5f929 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -34,7 +34,7 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm)
new_size = min(new_size, bo->base.base.size);
- mutex_lock(&bo->base.pages_lock);
+ dma_resv_lock(bo->base.base.resv, NULL);
if (bo->base.pages) {
pages = bo->base.pages;
@@ -42,7 +42,7 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm)
pages = kvmalloc_array(bo->base.base.size >> PAGE_SHIFT,
sizeof(*pages), GFP_KERNEL | __GFP_ZERO);
if (!pages) {
- mutex_unlock(&bo->base.pages_lock);
+ dma_resv_unlock(bo->base.base.resv);
return -ENOMEM;
}
@@ -56,13 +56,13 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm)
struct page *page = shmem_read_mapping_page(mapping, i);
if (IS_ERR(page)) {
- mutex_unlock(&bo->base.pages_lock);
+ dma_resv_unlock(bo->base.base.resv);
return PTR_ERR(page);
}
pages[i] = page;
}
- mutex_unlock(&bo->base.pages_lock);
+ dma_resv_unlock(bo->base.base.resv);
ret = sg_alloc_table_from_pages(&sgt, pages, i, 0,
new_size, GFP_KERNEL);
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index bbada731bbbd..d9dda6acdfac 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -407,6 +407,10 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
bo = to_panfrost_bo(gem_obj);
+ ret = dma_resv_lock_interruptible(bo->base.base.resv, NULL);
+ if (ret)
+ goto out_put_object;
+
mutex_lock(&pfdev->shrinker_lock);
mutex_lock(&bo->mappings.lock);
if (args->madv == PANFROST_MADV_DONTNEED) {
@@ -444,7 +448,8 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
out_unlock_mappings:
mutex_unlock(&bo->mappings.lock);
mutex_unlock(&pfdev->shrinker_lock);
-
+ dma_resv_unlock(bo->base.base.resv);
+out_put_object:
drm_gem_object_put(gem_obj);
return ret;
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
index bf0170782f25..6a71a2555f85 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
@@ -48,14 +48,14 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj)
if (!mutex_trylock(&bo->mappings.lock))
return false;
- if (!mutex_trylock(&shmem->pages_lock))
+ if (!dma_resv_trylock(shmem->base.resv))
goto unlock_mappings;
panfrost_gem_teardown_mappings_locked(bo);
- drm_gem_shmem_purge_locked(&bo->base);
+ drm_gem_shmem_purge(&bo->base);
ret = true;
- mutex_unlock(&shmem->pages_lock);
+ dma_resv_unlock(shmem->base.resv);
unlock_mappings:
mutex_unlock(&bo->mappings.lock);
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 666a5e53fe19..0679df57f394 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -443,6 +443,7 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
struct panfrost_gem_mapping *bomapping;
struct panfrost_gem_object *bo;
struct address_space *mapping;
+ struct drm_gem_object *obj;
pgoff_t page_offset;
struct sg_table *sgt;
struct page **pages;
@@ -465,15 +466,16 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
page_offset = addr >> PAGE_SHIFT;
page_offset -= bomapping->mmnode.start;
- mutex_lock(&bo->base.pages_lock);
+ obj = &bo->base.base;
+
+ dma_resv_lock(obj->resv, NULL);
if (!bo->base.pages) {
bo->sgts = kvmalloc_array(bo->base.base.size / SZ_2M,
sizeof(struct sg_table), GFP_KERNEL | __GFP_ZERO);
if (!bo->sgts) {
- mutex_unlock(&bo->base.pages_lock);
ret = -ENOMEM;
- goto err_bo;
+ goto err_unlock;
}
pages = kvmalloc_array(bo->base.base.size >> PAGE_SHIFT,
@@ -481,9 +483,8 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
if (!pages) {
kvfree(bo->sgts);
bo->sgts = NULL;
- mutex_unlock(&bo->base.pages_lock);
ret = -ENOMEM;
- goto err_bo;
+ goto err_unlock;
}
bo->base.pages = pages;
bo->base.pages_use_count = 1;
@@ -491,7 +492,6 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
pages = bo->base.pages;
if (pages[page_offset]) {
/* Pages are already mapped, bail out. */
- mutex_unlock(&bo->base.pages_lock);
goto out;
}
}
@@ -502,14 +502,11 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
for (i = page_offset; i < page_offset + NUM_FAULT_PAGES; i++) {
pages[i] = shmem_read_mapping_page(mapping, i);
if (IS_ERR(pages[i])) {
- mutex_unlock(&bo->base.pages_lock);
ret = PTR_ERR(pages[i]);
goto err_pages;
}
}
- mutex_unlock(&bo->base.pages_lock);
-
sgt = &bo->sgts[page_offset / (SZ_2M / PAGE_SIZE)];
ret = sg_alloc_table_from_pages(sgt, pages + page_offset,
NUM_FAULT_PAGES, 0, SZ_2M, GFP_KERNEL);
@@ -528,6 +525,8 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr);
out:
+ dma_resv_unlock(obj->resv);
+
panfrost_gem_mapping_put(bomapping);
return 0;
@@ -536,6 +535,8 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
sg_free_table(sgt);
err_pages:
drm_gem_shmem_put_pages(&bo->base);
+err_unlock:
+ dma_resv_unlock(obj->resv);
err_bo:
panfrost_gem_mapping_put(bomapping);
return ret;
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index 5994fed5e327..20ddcd799df9 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -26,11 +26,6 @@ struct drm_gem_shmem_object {
*/
struct drm_gem_object base;
- /**
- * @pages_lock: Protects the page table and use count
- */
- struct mutex pages_lock;
-
/**
* @pages: Page table
*/
@@ -65,11 +60,6 @@ struct drm_gem_shmem_object {
*/
struct sg_table *sgt;
- /**
- * @vmap_lock: Protects the vmap address and use count
- */
- struct mutex vmap_lock;
-
/**
* @vaddr: Kernel virtual address of the backing memory
*/
@@ -109,7 +99,6 @@ struct drm_gem_shmem_object {
struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size);
void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem);
-int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem);
void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem);
int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem);
void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem);
@@ -128,8 +117,7 @@ static inline bool drm_gem_shmem_is_purgeable(struct drm_gem_shmem_object *shmem
!shmem->base.dma_buf && !shmem->base.import_attach;
}
-void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem);
-bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem);
+void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem);
struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem);
struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem);
--
2.39.2
On 06/04/2023 18:06, Dmitry Osipenko wrote:
> Don't assert held dma-buf reservation lock on memory mapping of exported
> buffer.
>
> We're going to change dma-buf mmap() locking policy such that exporters
> will have to handle the lock. The previous locking policy caused deadlock
> problem for DRM drivers in a case of self-imported dma-bufs once these
> drivers are moved to use reservation lock universally. The problem is
> solved by moving the lock down to exporters. This patch prepares videobuf2
> for the locking policy update.
>
> Reviewed-by: Emil Velikov <[email protected]>
> Signed-off-by: Dmitry Osipenko <[email protected]>
Reviewed-by: Hans Verkuil <[email protected]>
Regards,
Hans
> ---
> drivers/media/common/videobuf2/videobuf2-dma-contig.c | 3 ---
> drivers/media/common/videobuf2/videobuf2-dma-sg.c | 3 ---
> drivers/media/common/videobuf2/videobuf2-vmalloc.c | 3 ---
> 3 files changed, 9 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index 205d3cac425c..2fa455d4a048 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -11,7 +11,6 @@
> */
>
> #include <linux/dma-buf.h>
> -#include <linux/dma-resv.h>
> #include <linux/module.h>
> #include <linux/refcount.h>
> #include <linux/scatterlist.h>
> @@ -456,8 +455,6 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct iosys_map *map)
> static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
> struct vm_area_struct *vma)
> {
> - dma_resv_assert_held(dbuf->resv);
> -
> return vb2_dc_mmap(dbuf->priv, vma);
> }
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> index 183037fb1273..28f3fdfe23a2 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> @@ -10,7 +10,6 @@
> * the Free Software Foundation.
> */
>
> -#include <linux/dma-resv.h>
> #include <linux/module.h>
> #include <linux/mm.h>
> #include <linux/refcount.h>
> @@ -498,8 +497,6 @@ static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf,
> static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
> struct vm_area_struct *vma)
> {
> - dma_resv_assert_held(dbuf->resv);
> -
> return vb2_dma_sg_mmap(dbuf->priv, vma);
> }
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> index a6c6d2fcaaa4..7c635e292106 100644
> --- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> +++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> @@ -10,7 +10,6 @@
> * the Free Software Foundation.
> */
>
> -#include <linux/dma-resv.h>
> #include <linux/io.h>
> #include <linux/module.h>
> #include <linux/mm.h>
> @@ -319,8 +318,6 @@ static int vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf,
> static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
> struct vm_area_struct *vma)
> {
> - dma_resv_assert_held(dbuf->resv);
> -
> return vb2_vmalloc_mmap(dbuf->priv, vma);
> }
>
On 4/6/23 19:06, Dmitry Osipenko wrote:
> Change locking policy of mmap() callback, making exporters responsible
> for handling dma-buf reservation locking. Previous locking policy stated
> that dma-buf is locked for both importers and exporters by the dma-buf
> core, which caused a deadlock problem for DRM drivers in a case of
> self-imported dma-bufs which required to take the lock from the DRM
> exporter side.
>
> Reviewed-by: Emil Velikov <[email protected]>
> Signed-off-by: Dmitry Osipenko <[email protected]>
> ---
> drivers/dma-buf/dma-buf.c | 17 +++--------------
> 1 file changed, 3 insertions(+), 14 deletions(-)
Christian, may I add yours ack to this patch?
--
Best regards,
Dmitry
On Thu, 06 Apr 2023 19:06:30 +0300, Dmitry Osipenko wrote:
> This patchset makes dma-buf exporters responisble for taking care of
> the reservation lock. I also included patch that moves drm-shmem to use
> reservation lock, to let CI test the whole set. I'm going to take all
> the patches via the drm-misc tree, please give an ack.
>
> Previous policy stated that dma-buf core takes the lock around mmap()
> callback. Which meant that both importers and exporters shouldn't touch
> the reservation lock in the mmap() code path. This worked well until
> Intel-CI found a deadlock problem in a case of self-imported dma-buf [1].
>
> [...]
Applied, thanks!
[4/7] fastrpc: Don't assert held reservation lock for dma-buf mmapping
commit: 3f6b4c6f0bd0126f673f3578429239ae3860718b
Best regards,
--
Srinivas Kandagatla <[email protected]>