Hello,
This series moves all drivers to a dynamic dma-buf locking specification.
From now on all dma-buf importers are made responsible for holding
dma-buf's reservation lock around all operations performed over dma-bufs
in accordance to the locking specification. This allows us to utilize
reservation lock more broadly around kernel without fearing of a potential
deadlocks.
This patchset passes all i915 selftests. It was also tested using VirtIO,
Panfrost, Lima, Tegra, udmabuf, AMDGPU and Nouveau drivers. I tested cases
of display+GPU, display+V4L and GPU+V4L dma-buf sharing (where appropriate),
which covers majority of kernel drivers since rest of the drivers share
same or similar code paths.
Changelog:
v6: - Added r-b from Michael Ruhl to the i915 patch.
- Added acks from Sumit Semwal and updated commit message of the
"Move dma_buf_vmap() to dynamic locking specification" patch like
was suggested by Sumit.
- Added "!dmabuf" check to dma_buf_vmap_unlocked() to match the locked
variant of the function, for consistency.
v5: - Added acks and r-bs that were given to v4.
- Changed i915 preparation patch like was suggested by Michael Ruhl.
The scope of reservation locking is smaller now.
v4: - Added dma_buf_mmap() to the "locking convention" documentation,
which was missed by accident in v3.
- Added acks from Christian König, Tomasz Figa and Hans Verkuil that
they gave to couple v3 patches.
- Dropped the "_unlocked" postfix from function names that don't have
the locked variant, as was requested by Christian König.
- Factored out the per-driver preparations into separate patches
to ease reviewing of the changes, which is now doable without the
global dma-buf functions renaming.
- Factored out the dynamic locking convention enforcements into separate
patches which add the final dma_resv_assert_held(dmabuf->resv) to the
dma-buf API functions.
v3: - Factored out dma_buf_mmap_unlocked() and attachment functions
into aseparate patches, like was suggested by Christian König.
- Corrected and factored out dma-buf locking documentation into
a separate patch, like was suggested by Christian König.
- Intel driver dropped the reservation locking fews days ago from
its BO-release code path, but we need that locking for the imported
GEMs because in the end that code path unmaps the imported GEM.
So I added back the locking needed by the imported GEMs, updating
the "dma-buf attachment locking specification" patch appropriately.
- Tested Nouveau+Intel dma-buf import/export combo.
- Tested udmabuf import to i915/Nouveau/AMDGPU.
- Fixed few places in Etnaviv, Panfrost and Lima drivers that I missed
to switch to locked dma-buf vmapping in the drm/gem: Take reservation
lock for vmap/vunmap operations" patch. In a result invalidated the
Christian's r-b that he gave to v2.
- Added locked dma-buf vmap/vunmap functions that are needed for fixing
vmappping of Etnaviv, Panfrost and Lima drivers mentioned above.
I actually had this change stashed for the drm-shmem shrinker patchset,
but then realized that it's already needed by the dma-buf patches.
Also improved my tests to better cover these code paths.
v2: - Changed locking specification to avoid problems with a cross-driver
ww locking, like was suggested by Christian König. Now the attach/detach
callbacks are invoked without the held lock and exporter should take the
lock.
- Added "locking convention" documentation that explains which dma-buf
functions and callbacks are locked/unlocked for importers and exporters,
which was requested by Christian König.
- Added ack from Tomasz Figa to the V4L patches that he gave to v1.
Dmitry Osipenko (21):
dma-buf: Add unlocked variant of vmapping functions
dma-buf: Add unlocked variant of attachment-mapping functions
drm/gem: Take reservation lock for vmap/vunmap operations
drm/prime: Prepare to dynamic dma-buf locking specification
drm/armada: Prepare to dynamic dma-buf locking specification
drm/i915: Prepare to dynamic dma-buf locking specification
drm/omapdrm: Prepare to dynamic dma-buf locking specification
drm/tegra: Prepare to dynamic dma-buf locking specification
drm/etnaviv: Prepare to dynamic dma-buf locking specification
RDMA/umem: Prepare to dynamic dma-buf locking specification
misc: fastrpc: Prepare to dynamic dma-buf locking specification
xen/gntdev: Prepare to dynamic dma-buf locking specification
media: videobuf2: Prepare to dynamic dma-buf locking specification
media: tegra-vde: Prepare to dynamic dma-buf locking specification
dma-buf: Move dma_buf_vmap() to dynamic locking specification
dma-buf: Move dma_buf_attach() to dynamic locking specification
dma-buf: Move dma_buf_map_attachment() to dynamic locking
specification
dma-buf: Move dma_buf_mmap() to dynamic locking specification
dma-buf: Document dynamic locking convention
media: videobuf2: Stop using internal dma-buf lock
dma-buf: Remove obsoleted internal lock
Documentation/driver-api/dma-buf.rst | 6 +
drivers/dma-buf/dma-buf.c | 214 +++++++++++++++---
drivers/gpu/drm/armada/armada_gem.c | 8 +-
drivers/gpu/drm/drm_client.c | 4 +-
drivers/gpu/drm/drm_gem.c | 24 ++
drivers/gpu/drm/drm_gem_dma_helper.c | 6 +-
drivers/gpu/drm/drm_gem_framebuffer_helper.c | 6 +-
drivers/gpu/drm/drm_gem_ttm_helper.c | 9 +-
drivers/gpu/drm/drm_prime.c | 6 +-
drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_object.c | 14 ++
.../drm/i915/gem/selftests/i915_gem_dmabuf.c | 16 +-
drivers/gpu/drm/lima/lima_sched.c | 4 +-
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 4 +-
drivers/gpu/drm/panfrost/panfrost_dump.c | 4 +-
drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 6 +-
drivers/gpu/drm/qxl/qxl_object.c | 17 +-
drivers/gpu/drm/qxl/qxl_prime.c | 4 +-
drivers/gpu/drm/tegra/gem.c | 17 +-
drivers/infiniband/core/umem_dmabuf.c | 7 +-
.../common/videobuf2/videobuf2-dma-contig.c | 22 +-
.../media/common/videobuf2/videobuf2-dma-sg.c | 19 +-
.../common/videobuf2/videobuf2-vmalloc.c | 17 +-
.../platform/nvidia/tegra-vde/dmabuf-cache.c | 6 +-
drivers/misc/fastrpc.c | 6 +-
drivers/xen/gntdev-dmabuf.c | 8 +-
include/drm/drm_gem.h | 3 +
include/linux/dma-buf.h | 17 +-
29 files changed, 323 insertions(+), 155 deletions(-)
--
2.37.3
Prepare DRM prime core to the common dynamic dma-buf locking convention
by starting to use the unlocked versions of dma-buf API functions.
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/drm_prime.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index eb09e86044c6..20e109a802ae 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -940,7 +940,7 @@ struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
get_dma_buf(dma_buf);
- sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+ sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
goto fail_detach;
@@ -958,7 +958,7 @@ struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
return obj;
fail_unmap:
- dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+ dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
fail_detach:
dma_buf_detach(dma_buf, attach);
dma_buf_put(dma_buf);
@@ -1056,7 +1056,7 @@ void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
attach = obj->import_attach;
if (sg)
- dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
+ dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
dma_buf = attach->dmabuf;
dma_buf_detach(attach->dmabuf, attach);
/* remove the reference */
--
2.37.3
Move dma_buf_mmap() function to the dynamic locking specification by
taking the reservation lock. Neither of the today's drivers take the
reservation lock within the mmap() callback, hence it's safe to enforce
the locking.
Acked-by: Sumit Semwal <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index bff5a70b8735..2452b4c82584 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1390,6 +1390,8 @@ 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;
@@ -1410,7 +1412,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
vma_set_file(vma, dmabuf->file);
vma->vm_pgoff = pgoff;
- return dmabuf->ops->mmap(dmabuf, vma);
+ dma_resv_lock(dmabuf->resv, NULL);
+ ret = dmabuf->ops->mmap(dmabuf, vma);
+ dma_resv_unlock(dmabuf->resv);
+
+ return ret;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
--
2.37.3
Prepare Tegra DRM driver to the common dynamic dma-buf locking convention
by starting to use the unlocked versions of dma-buf API functions.
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/tegra/gem.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 81991090adcc..b09b8ab40ae4 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -84,7 +84,7 @@ static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_
goto free;
}
- map->sgt = dma_buf_map_attachment(map->attach, direction);
+ map->sgt = dma_buf_map_attachment_unlocked(map->attach, direction);
if (IS_ERR(map->sgt)) {
dma_buf_detach(buf, map->attach);
err = PTR_ERR(map->sgt);
@@ -160,7 +160,8 @@ static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_
static void tegra_bo_unpin(struct host1x_bo_mapping *map)
{
if (map->attach) {
- dma_buf_unmap_attachment(map->attach, map->sgt, map->direction);
+ dma_buf_unmap_attachment_unlocked(map->attach, map->sgt,
+ map->direction);
dma_buf_detach(map->attach->dmabuf, map->attach);
} else {
dma_unmap_sgtable(map->dev, map->sgt, map->direction, 0);
@@ -181,7 +182,7 @@ static void *tegra_bo_mmap(struct host1x_bo *bo)
if (obj->vaddr) {
return obj->vaddr;
} else if (obj->gem.import_attach) {
- ret = dma_buf_vmap(obj->gem.import_attach->dmabuf, &map);
+ ret = dma_buf_vmap_unlocked(obj->gem.import_attach->dmabuf, &map);
return ret ? NULL : map.vaddr;
} else {
return vmap(obj->pages, obj->num_pages, VM_MAP,
@@ -197,7 +198,7 @@ static void tegra_bo_munmap(struct host1x_bo *bo, void *addr)
if (obj->vaddr)
return;
else if (obj->gem.import_attach)
- dma_buf_vunmap(obj->gem.import_attach->dmabuf, &map);
+ dma_buf_vunmap_unlocked(obj->gem.import_attach->dmabuf, &map);
else
vunmap(addr);
}
@@ -461,7 +462,7 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
get_dma_buf(buf);
- bo->sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
+ bo->sgt = dma_buf_map_attachment_unlocked(attach, DMA_TO_DEVICE);
if (IS_ERR(bo->sgt)) {
err = PTR_ERR(bo->sgt);
goto detach;
@@ -479,7 +480,7 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
detach:
if (!IS_ERR_OR_NULL(bo->sgt))
- dma_buf_unmap_attachment(attach, bo->sgt, DMA_TO_DEVICE);
+ dma_buf_unmap_attachment_unlocked(attach, bo->sgt, DMA_TO_DEVICE);
dma_buf_detach(buf, attach);
dma_buf_put(buf);
@@ -508,8 +509,8 @@ void tegra_bo_free_object(struct drm_gem_object *gem)
tegra_bo_iommu_unmap(tegra, bo);
if (gem->import_attach) {
- dma_buf_unmap_attachment(gem->import_attach, bo->sgt,
- DMA_TO_DEVICE);
+ dma_buf_unmap_attachment_unlocked(gem->import_attach, bo->sgt,
+ DMA_TO_DEVICE);
drm_prime_gem_destroy(gem, NULL);
} else {
tegra_bo_free(gem->dev, bo);
--
2.37.3
Add unlocked variant of dma_buf_vmap/vunmap() that will be utilized
by drivers that don't take the reservation lock explicitly.
Acked-by: Sumit Semwal <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 41 +++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 2 ++
2 files changed, 43 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index dd0f83ee505b..0427f3b88170 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1425,6 +1425,31 @@ int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, DMA_BUF);
+/**
+ * dma_buf_vmap_unlocked - Create virtual mapping for the buffer object into kernel
+ * address space. Same restrictions as for vmap and friends apply.
+ * @dmabuf: [in] buffer to vmap
+ * @map: [out] returns the vmap pointer
+ *
+ * Unlocked version of dma_buf_vmap()
+ *
+ * Returns 0 on success, or a negative errno code otherwise.
+ */
+int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map)
+{
+ int ret;
+
+ if (WARN_ON(!dmabuf))
+ return -EINVAL;
+
+ dma_resv_lock(dmabuf->resv, NULL);
+ ret = dma_buf_vmap(dmabuf, map);
+ dma_resv_unlock(dmabuf->resv);
+
+ return ret;
+}
+EXPORT_SYMBOL_NS_GPL(dma_buf_vmap_unlocked, DMA_BUF);
+
/**
* dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
* @dmabuf: [in] buffer to vunmap
@@ -1449,6 +1474,22 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map)
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF);
+/**
+ * dma_buf_vunmap_unlocked - Unmap a vmap obtained by dma_buf_vmap.
+ * @dmabuf: [in] buffer to vunmap
+ * @map: [in] vmap pointer to vunmap
+ */
+void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map)
+{
+ if (WARN_ON(!dmabuf))
+ return;
+
+ dma_resv_lock(dmabuf->resv, NULL);
+ dma_buf_vunmap(dmabuf, map);
+ dma_resv_unlock(dmabuf->resv);
+}
+EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap_unlocked, DMA_BUF);
+
#ifdef CONFIG_DEBUG_FS
static int dma_buf_debug_show(struct seq_file *s, void *unused)
{
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 71731796c8c3..8daa054dd7fe 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -632,4 +632,6 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
unsigned long);
int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map);
void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map);
+int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map);
+void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map);
#endif /* __DMA_BUF_H__ */
--
2.37.3
Move dma-buf attachment API functions to the dynamic locking specification
by taking the reservation lock around the mapping operations. The strict
locking convention prevents deadlock situations for dma-buf importers and
exporters.
Acked-by: Sumit Semwal <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 23656f334735..d60585bbb529 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -859,8 +859,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
dma_buf_is_dynamic(dmabuf)) {
struct sg_table *sgt;
+ dma_resv_lock(attach->dmabuf->resv, NULL);
if (dma_buf_is_dynamic(attach->dmabuf)) {
- dma_resv_lock(attach->dmabuf->resv, NULL);
ret = dmabuf->ops->pin(attach);
if (ret)
goto err_unlock;
@@ -873,8 +873,7 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
ret = PTR_ERR(sgt);
goto err_unpin;
}
- if (dma_buf_is_dynamic(attach->dmabuf))
- dma_resv_unlock(attach->dmabuf->resv);
+ dma_resv_unlock(attach->dmabuf->resv);
attach->sgt = sgt;
attach->dir = DMA_BIDIRECTIONAL;
}
@@ -890,8 +889,7 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
dmabuf->ops->unpin(attach);
err_unlock:
- if (dma_buf_is_dynamic(attach->dmabuf))
- dma_resv_unlock(attach->dmabuf->resv);
+ dma_resv_unlock(attach->dmabuf->resv);
dma_buf_detach(dmabuf, attach);
return ERR_PTR(ret);
@@ -937,21 +935,19 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
if (WARN_ON(!dmabuf || !attach))
return;
+ dma_resv_lock(attach->dmabuf->resv, NULL);
+
if (attach->sgt) {
- if (dma_buf_is_dynamic(attach->dmabuf))
- dma_resv_lock(attach->dmabuf->resv, NULL);
__unmap_dma_buf(attach, attach->sgt, attach->dir);
- if (dma_buf_is_dynamic(attach->dmabuf)) {
+ if (dma_buf_is_dynamic(attach->dmabuf))
dmabuf->ops->unpin(attach);
- dma_resv_unlock(attach->dmabuf->resv);
- }
}
-
- dma_resv_lock(dmabuf->resv, NULL);
list_del(&attach->node);
+
dma_resv_unlock(dmabuf->resv);
+
if (dmabuf->ops->detach)
dmabuf->ops->detach(dmabuf, attach);
--
2.37.3
Prepare Tegra video decoder driver to the common dynamic dma-buf
locking convention by starting to use the unlocked versions of dma-buf
API functions.
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c b/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c
index 69c346148070..1c5b94989aec 100644
--- a/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c
+++ b/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c
@@ -38,7 +38,7 @@ static void tegra_vde_release_entry(struct tegra_vde_cache_entry *entry)
if (entry->vde->domain)
tegra_vde_iommu_unmap(entry->vde, entry->iova);
- dma_buf_unmap_attachment(entry->a, entry->sgt, entry->dma_dir);
+ dma_buf_unmap_attachment_unlocked(entry->a, entry->sgt, entry->dma_dir);
dma_buf_detach(dmabuf, entry->a);
dma_buf_put(dmabuf);
@@ -102,7 +102,7 @@ int tegra_vde_dmabuf_cache_map(struct tegra_vde *vde,
goto err_unlock;
}
- sgt = dma_buf_map_attachment(attachment, dma_dir);
+ sgt = dma_buf_map_attachment_unlocked(attachment, dma_dir);
if (IS_ERR(sgt)) {
dev_err(dev, "Failed to get dmabufs sg_table\n");
err = PTR_ERR(sgt);
@@ -152,7 +152,7 @@ int tegra_vde_dmabuf_cache_map(struct tegra_vde *vde,
err_free:
kfree(entry);
err_unmap:
- dma_buf_unmap_attachment(attachment, sgt, dma_dir);
+ dma_buf_unmap_attachment_unlocked(attachment, sgt, dma_dir);
err_detach:
dma_buf_detach(dmabuf, attachment);
err_unlock:
--
2.37.3
Prepare InfiniBand drivers to the common dynamic dma-buf locking
convention by starting to use the unlocked versions of dma-buf API
functions.
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/infiniband/core/umem_dmabuf.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
index 04c04e6d24c3..43b26bc12288 100644
--- a/drivers/infiniband/core/umem_dmabuf.c
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -26,7 +26,8 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
if (umem_dmabuf->sgt)
goto wait_fence;
- sgt = dma_buf_map_attachment(umem_dmabuf->attach, DMA_BIDIRECTIONAL);
+ sgt = dma_buf_map_attachment_unlocked(umem_dmabuf->attach,
+ DMA_BIDIRECTIONAL);
if (IS_ERR(sgt))
return PTR_ERR(sgt);
@@ -102,8 +103,8 @@ void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
umem_dmabuf->last_sg_trim = 0;
}
- dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
- DMA_BIDIRECTIONAL);
+ dma_buf_unmap_attachment_unlocked(umem_dmabuf->attach, umem_dmabuf->sgt,
+ DMA_BIDIRECTIONAL);
umem_dmabuf->sgt = NULL;
}
--
2.37.3
The internal dma-buf lock isn't needed anymore because the updated
locking specification claims that dma-buf reservation must be locked
by importers, and thus, the internal data is already protected by the
reservation lock. Remove the obsoleted internal lock.
Acked-by: Sumit Semwal <[email protected]>
Acked-by: Christian König <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 14 ++++----------
include/linux/dma-buf.h | 9 ---------
2 files changed, 4 insertions(+), 19 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index e04d504441a5..82f72b5647f8 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -657,7 +657,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
dmabuf->file = file;
- mutex_init(&dmabuf->lock);
INIT_LIST_HEAD(&dmabuf->attachments);
mutex_lock(&db_list.lock);
@@ -1503,7 +1502,7 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
{
struct iosys_map ptr;
- int ret = 0;
+ int ret;
iosys_map_clear(map);
@@ -1515,28 +1514,25 @@ int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
if (!dmabuf->ops->vmap)
return -EINVAL;
- mutex_lock(&dmabuf->lock);
if (dmabuf->vmapping_counter) {
dmabuf->vmapping_counter++;
BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
*map = dmabuf->vmap_ptr;
- goto out_unlock;
+ return 0;
}
BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr));
ret = dmabuf->ops->vmap(dmabuf, &ptr);
if (WARN_ON_ONCE(ret))
- goto out_unlock;
+ return ret;
dmabuf->vmap_ptr = ptr;
dmabuf->vmapping_counter = 1;
*map = dmabuf->vmap_ptr;
-out_unlock:
- mutex_unlock(&dmabuf->lock);
- return ret;
+ return 0;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, DMA_BUF);
@@ -1581,13 +1577,11 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map)
BUG_ON(dmabuf->vmapping_counter == 0);
BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map));
- mutex_lock(&dmabuf->lock);
if (--dmabuf->vmapping_counter == 0) {
if (dmabuf->ops->vunmap)
dmabuf->ops->vunmap(dmabuf, map);
iosys_map_clear(&dmabuf->vmap_ptr);
}
- mutex_unlock(&dmabuf->lock);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index f11b5bbc2f37..6fa8d4e29719 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -326,15 +326,6 @@ struct dma_buf {
/** @ops: dma_buf_ops associated with this buffer object. */
const struct dma_buf_ops *ops;
- /**
- * @lock:
- *
- * Used internally to serialize list manipulation, attach/detach and
- * vmap/unmap. Note that in many cases this is superseeded by
- * dma_resv_lock() on @resv.
- */
- struct mutex lock;
-
/**
* @vmapping_counter:
*
--
2.37.3
Move dma-buf attachment mapping functions to the dynamic locking
specification by asserting that the reservation lock is held.
Acked-by: Sumit Semwal <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index d60585bbb529..bff5a70b8735 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1038,8 +1038,7 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
if (WARN_ON(!attach || !attach->dmabuf))
return ERR_PTR(-EINVAL);
- if (dma_buf_attachment_is_dynamic(attach))
- dma_resv_assert_held(attach->dmabuf->resv);
+ dma_resv_assert_held(attach->dmabuf->resv);
if (attach->sgt) {
/*
@@ -1054,7 +1053,6 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
}
if (dma_buf_is_dynamic(attach->dmabuf)) {
- dma_resv_assert_held(attach->dmabuf->resv);
if (!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) {
r = attach->dmabuf->ops->pin(attach);
if (r)
@@ -1143,15 +1141,11 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
return;
- if (dma_buf_attachment_is_dynamic(attach))
- dma_resv_assert_held(attach->dmabuf->resv);
+ dma_resv_assert_held(attach->dmabuf->resv);
if (attach->sgt == sg_table)
return;
- if (dma_buf_is_dynamic(attach->dmabuf))
- dma_resv_assert_held(attach->dmabuf->resv);
-
__unmap_dma_buf(attach, sg_table, direction);
if (dma_buf_is_dynamic(attach->dmabuf) &&
--
2.37.3
Prepare i915 driver to the common dynamic dma-buf locking convention
by starting to use the unlocked versions of dma-buf API functions
and handling cases where importer now holds the reservation lock.
Acked-by: Christian König <[email protected]>
Reviewed-by: Michael J. Ruhl <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_object.c | 14 ++++++++++++++
.../gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c | 16 ++++++++--------
3 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index f5062d0c6333..07eee1c09aaf 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -72,7 +72,7 @@ static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf,
struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
void *vaddr;
- vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
+ vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
if (IS_ERR(vaddr))
return PTR_ERR(vaddr);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 7ff9c7877bec..3e3f63f86629 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -290,7 +290,21 @@ void __i915_gem_object_pages_fini(struct drm_i915_gem_object *obj)
__i915_gem_object_free_mmaps(obj);
atomic_set(&obj->mm.pages_pin_count, 0);
+
+ /*
+ * dma_buf_unmap_attachment() requires reservation to be
+ * locked. The imported GEM shouldn't share reservation lock
+ * and ttm_bo_cleanup_memtype_use() shouldn't be invoked for
+ * dma-buf, so it's safe to take the lock.
+ */
+ if (obj->base.import_attach)
+ i915_gem_object_lock(obj, NULL);
+
__i915_gem_object_put_pages(obj);
+
+ if (obj->base.import_attach)
+ i915_gem_object_unlock(obj);
+
GEM_BUG_ON(i915_gem_object_has_pages(obj));
}
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
index 51ed824b020c..f2f3cfad807b 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
@@ -213,7 +213,7 @@ static int igt_dmabuf_import_same_driver(struct drm_i915_private *i915,
goto out_import;
}
- st = dma_buf_map_attachment(import_attach, DMA_BIDIRECTIONAL);
+ st = dma_buf_map_attachment_unlocked(import_attach, DMA_BIDIRECTIONAL);
if (IS_ERR(st)) {
err = PTR_ERR(st);
goto out_detach;
@@ -226,7 +226,7 @@ static int igt_dmabuf_import_same_driver(struct drm_i915_private *i915,
timeout = -ETIME;
}
err = timeout > 0 ? 0 : timeout;
- dma_buf_unmap_attachment(import_attach, st, DMA_BIDIRECTIONAL);
+ dma_buf_unmap_attachment_unlocked(import_attach, st, DMA_BIDIRECTIONAL);
out_detach:
dma_buf_detach(dmabuf, import_attach);
out_import:
@@ -296,7 +296,7 @@ static int igt_dmabuf_import(void *arg)
goto out_obj;
}
- err = dma_buf_vmap(dmabuf, &map);
+ err = dma_buf_vmap_unlocked(dmabuf, &map);
dma_map = err ? NULL : map.vaddr;
if (!dma_map) {
pr_err("dma_buf_vmap failed\n");
@@ -337,7 +337,7 @@ static int igt_dmabuf_import(void *arg)
err = 0;
out_dma_map:
- dma_buf_vunmap(dmabuf, &map);
+ dma_buf_vunmap_unlocked(dmabuf, &map);
out_obj:
i915_gem_object_put(obj);
out_dmabuf:
@@ -358,7 +358,7 @@ static int igt_dmabuf_import_ownership(void *arg)
if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);
- err = dma_buf_vmap(dmabuf, &map);
+ err = dma_buf_vmap_unlocked(dmabuf, &map);
ptr = err ? NULL : map.vaddr;
if (!ptr) {
pr_err("dma_buf_vmap failed\n");
@@ -367,7 +367,7 @@ static int igt_dmabuf_import_ownership(void *arg)
}
memset(ptr, 0xc5, PAGE_SIZE);
- dma_buf_vunmap(dmabuf, &map);
+ dma_buf_vunmap_unlocked(dmabuf, &map);
obj = to_intel_bo(i915_gem_prime_import(&i915->drm, dmabuf));
if (IS_ERR(obj)) {
@@ -418,7 +418,7 @@ static int igt_dmabuf_export_vmap(void *arg)
}
i915_gem_object_put(obj);
- err = dma_buf_vmap(dmabuf, &map);
+ err = dma_buf_vmap_unlocked(dmabuf, &map);
ptr = err ? NULL : map.vaddr;
if (!ptr) {
pr_err("dma_buf_vmap failed\n");
@@ -435,7 +435,7 @@ static int igt_dmabuf_export_vmap(void *arg)
memset(ptr, 0xc5, dmabuf->size);
err = 0;
- dma_buf_vunmap(dmabuf, &map);
+ dma_buf_vunmap_unlocked(dmabuf, &map);
out:
dma_buf_put(dmabuf);
return err;
--
2.37.3
Prepare Armada driver to the common dynamic dma-buf locking convention
by starting to use the unlocked versions of dma-buf API functions.
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/armada/armada_gem.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index 5430265ad458..26d10065d534 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -66,8 +66,8 @@ void armada_gem_free_object(struct drm_gem_object *obj)
if (dobj->obj.import_attach) {
/* We only ever display imported data */
if (dobj->sgt)
- dma_buf_unmap_attachment(dobj->obj.import_attach,
- dobj->sgt, DMA_TO_DEVICE);
+ dma_buf_unmap_attachment_unlocked(dobj->obj.import_attach,
+ dobj->sgt, DMA_TO_DEVICE);
drm_prime_gem_destroy(&dobj->obj, NULL);
}
@@ -539,8 +539,8 @@ int armada_gem_map_import(struct armada_gem_object *dobj)
{
int ret;
- dobj->sgt = dma_buf_map_attachment(dobj->obj.import_attach,
- DMA_TO_DEVICE);
+ dobj->sgt = dma_buf_map_attachment_unlocked(dobj->obj.import_attach,
+ DMA_TO_DEVICE);
if (IS_ERR(dobj->sgt)) {
ret = PTR_ERR(dobj->sgt);
dobj->sgt = NULL;
--
2.37.3
Add documentation for the dynamic locking convention. The documentation
tells dma-buf API users when they should take the reservation lock and
when not.
Acked-by: Sumit Semwal <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
Documentation/driver-api/dma-buf.rst | 6 +++
drivers/dma-buf/dma-buf.c | 64 ++++++++++++++++++++++++++++
2 files changed, 70 insertions(+)
diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst
index 36a76cbe9095..622b8156d212 100644
--- a/Documentation/driver-api/dma-buf.rst
+++ b/Documentation/driver-api/dma-buf.rst
@@ -119,6 +119,12 @@ DMA Buffer ioctls
.. kernel-doc:: include/uapi/linux/dma-buf.h
+DMA-BUF locking convention
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/dma-buf/dma-buf.c
+ :doc: locking convention
+
Kernel Functions and Structures Reference
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 2452b4c82584..e04d504441a5 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -795,6 +795,70 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
return sg_table;
}
+/**
+ * DOC: locking convention
+ *
+ * In order to avoid deadlock situations between dma-buf exports and importers,
+ * all dma-buf API users must follow the common dma-buf locking convention.
+ *
+ * Convention for importers
+ *
+ * 1. Importers must hold the dma-buf reservation lock when calling these
+ * functions:
+ *
+ * - dma_buf_pin()
+ * - dma_buf_unpin()
+ * - dma_buf_map_attachment()
+ * - dma_buf_unmap_attachment()
+ * - dma_buf_vmap()
+ * - dma_buf_vunmap()
+ *
+ * 2. Importers must not hold the dma-buf reservation lock when calling these
+ * functions:
+ *
+ * - dma_buf_attach()
+ * - dma_buf_dynamic_attach()
+ * - dma_buf_detach()
+ * - dma_buf_export(
+ * - dma_buf_fd()
+ * - dma_buf_get()
+ * - dma_buf_put()
+ * - dma_buf_mmap()
+ * - dma_buf_begin_cpu_access()
+ * - dma_buf_end_cpu_access()
+ * - dma_buf_map_attachment_unlocked()
+ * - dma_buf_unmap_attachment_unlocked()
+ * - dma_buf_vmap_unlocked()
+ * - dma_buf_vunmap_unlocked()
+ *
+ * Convention for exporters
+ *
+ * 1. These &dma_buf_ops callbacks are invoked with unlocked dma-buf
+ * reservation and exporter can take the lock:
+ *
+ * - &dma_buf_ops.attach()
+ * - &dma_buf_ops.detach()
+ * - &dma_buf_ops.release()
+ * - &dma_buf_ops.begin_cpu_access()
+ * - &dma_buf_ops.end_cpu_access()
+ *
+ * 2. These &dma_buf_ops callbacks are invoked with locked dma-buf
+ * reservation and exporter can't take the lock:
+ *
+ * - &dma_buf_ops.pin()
+ * - &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()
+ *
+ * 3. Exporters must hold the dma-buf reservation lock when calling these
+ * functions:
+ *
+ * - dma_buf_move_notify()
+ */
+
/**
* dma_buf_dynamic_attach - Add the device to dma_buf's attachments list
* @dmabuf: [in] buffer to attach device to.
--
2.37.3
Prepare V4L2 memory allocators to the common dynamic dma-buf locking
convention by starting to use the unlocked versions of dma-buf API
functions.
Acked-by: Tomasz Figa <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/media/common/videobuf2/videobuf2-dma-contig.c | 11 ++++++-----
drivers/media/common/videobuf2/videobuf2-dma-sg.c | 8 ++++----
drivers/media/common/videobuf2/videobuf2-vmalloc.c | 6 +++---
3 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 678b359717c4..79f4d8301fbb 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -101,7 +101,7 @@ static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
if (buf->db_attach) {
struct iosys_map map;
- if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
+ if (!dma_buf_vmap_unlocked(buf->db_attach->dmabuf, &map))
buf->vaddr = map.vaddr;
return buf->vaddr;
@@ -711,7 +711,7 @@ static int vb2_dc_map_dmabuf(void *mem_priv)
}
/* get the associated scatterlist for this buffer */
- sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
+ sgt = dma_buf_map_attachment_unlocked(buf->db_attach, buf->dma_dir);
if (IS_ERR(sgt)) {
pr_err("Error getting dmabuf scatterlist\n");
return -EINVAL;
@@ -722,7 +722,8 @@ static int vb2_dc_map_dmabuf(void *mem_priv)
if (contig_size < buf->size) {
pr_err("contiguous chunk is too small %lu/%lu\n",
contig_size, buf->size);
- dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+ dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt,
+ buf->dma_dir);
return -EFAULT;
}
@@ -750,10 +751,10 @@ static void vb2_dc_unmap_dmabuf(void *mem_priv)
}
if (buf->vaddr) {
- dma_buf_vunmap(buf->db_attach->dmabuf, &map);
+ dma_buf_vunmap_unlocked(buf->db_attach->dmabuf, &map);
buf->vaddr = NULL;
}
- dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+ dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt, buf->dma_dir);
buf->dma_addr = 0;
buf->dma_sgt = NULL;
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index fa69158a65b1..36ecdea8d707 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -309,7 +309,7 @@ static void *vb2_dma_sg_vaddr(struct vb2_buffer *vb, void *buf_priv)
if (!buf->vaddr) {
if (buf->db_attach) {
- ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
+ ret = dma_buf_vmap_unlocked(buf->db_attach->dmabuf, &map);
buf->vaddr = ret ? NULL : map.vaddr;
} else {
buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1);
@@ -565,7 +565,7 @@ static int vb2_dma_sg_map_dmabuf(void *mem_priv)
}
/* get the associated scatterlist for this buffer */
- sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
+ sgt = dma_buf_map_attachment_unlocked(buf->db_attach, buf->dma_dir);
if (IS_ERR(sgt)) {
pr_err("Error getting dmabuf scatterlist\n");
return -EINVAL;
@@ -594,10 +594,10 @@ static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
}
if (buf->vaddr) {
- dma_buf_vunmap(buf->db_attach->dmabuf, &map);
+ dma_buf_vunmap_unlocked(buf->db_attach->dmabuf, &map);
buf->vaddr = NULL;
}
- dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+ dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt, buf->dma_dir);
buf->dma_sgt = NULL;
}
diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
index 948152f1596b..7831bf545874 100644
--- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
+++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
@@ -376,7 +376,7 @@ static int vb2_vmalloc_map_dmabuf(void *mem_priv)
struct iosys_map map;
int ret;
- ret = dma_buf_vmap(buf->dbuf, &map);
+ ret = dma_buf_vmap_unlocked(buf->dbuf, &map);
if (ret)
return -EFAULT;
buf->vaddr = map.vaddr;
@@ -389,7 +389,7 @@ static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
struct vb2_vmalloc_buf *buf = mem_priv;
struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);
- dma_buf_vunmap(buf->dbuf, &map);
+ dma_buf_vunmap_unlocked(buf->dbuf, &map);
buf->vaddr = NULL;
}
@@ -399,7 +399,7 @@ static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);
if (buf->vaddr)
- dma_buf_vunmap(buf->dbuf, &map);
+ dma_buf_vunmap_unlocked(buf->dbuf, &map);
kfree(buf);
}
--
2.37.3
Add unlocked variant of dma_buf_map/unmap_attachment() that will
be used by drivers that don't take the reservation lock explicitly.
Acked-by: Sumit Semwal <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/dma-buf/dma-buf.c | 53 +++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 6 +++++
2 files changed, 59 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 0427f3b88170..f349613790a6 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1100,6 +1100,34 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
}
EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment, DMA_BUF);
+/**
+ * dma_buf_map_attachment_unlocked - Returns the scatterlist table of the attachment;
+ * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
+ * dma_buf_ops.
+ * @attach: [in] attachment whose scatterlist is to be returned
+ * @direction: [in] direction of DMA transfer
+ *
+ * Unlocked variant of dma_buf_map_attachment().
+ */
+struct sg_table *
+dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
+ enum dma_data_direction direction)
+{
+ struct sg_table *sg_table;
+
+ might_sleep();
+
+ if (WARN_ON(!attach || !attach->dmabuf))
+ return ERR_PTR(-EINVAL);
+
+ dma_resv_lock(attach->dmabuf->resv, NULL);
+ sg_table = dma_buf_map_attachment(attach, direction);
+ dma_resv_unlock(attach->dmabuf->resv);
+
+ return sg_table;
+}
+EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment_unlocked, DMA_BUF);
+
/**
* dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
* deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
@@ -1136,6 +1164,31 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
}
EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment, DMA_BUF);
+/**
+ * dma_buf_unmap_attachment_unlocked - unmaps and decreases usecount of the buffer;might
+ * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
+ * dma_buf_ops.
+ * @attach: [in] attachment to unmap buffer from
+ * @sg_table: [in] scatterlist info of the buffer to unmap
+ * @direction: [in] direction of DMA transfer
+ *
+ * Unlocked variant of dma_buf_unmap_attachment().
+ */
+void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
+ struct sg_table *sg_table,
+ enum dma_data_direction direction)
+{
+ might_sleep();
+
+ if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
+ return;
+
+ dma_resv_lock(attach->dmabuf->resv, NULL);
+ dma_buf_unmap_attachment(attach, sg_table, direction);
+ dma_resv_unlock(attach->dmabuf->resv);
+}
+EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment_unlocked, DMA_BUF);
+
/**
* dma_buf_move_notify - notify attachments that DMA-buf is moving
*
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 8daa054dd7fe..f11b5bbc2f37 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -627,6 +627,12 @@ int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
enum dma_data_direction dir);
int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
enum dma_data_direction dir);
+struct sg_table *
+dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
+ enum dma_data_direction direction);
+void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
+ struct sg_table *sg_table,
+ enum dma_data_direction direction);
int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
unsigned long);
--
2.37.3
All drivers that use dma-bufs have been moved to the updated locking
specification and now dma-buf reservation is guaranteed to be locked
by importers during the mapping operations. There is no need to take
the internal dma-buf lock anymore. Remove locking from the videobuf2
memory allocators.
Acked-by: Tomasz Figa <[email protected]>
Acked-by: Hans Verkuil <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/media/common/videobuf2/videobuf2-dma-contig.c | 11 +----------
drivers/media/common/videobuf2/videobuf2-dma-sg.c | 11 +----------
drivers/media/common/videobuf2/videobuf2-vmalloc.c | 11 +----------
3 files changed, 3 insertions(+), 30 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 79f4d8301fbb..555bd40fa472 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -382,18 +382,12 @@ static struct sg_table *vb2_dc_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
{
struct vb2_dc_attachment *attach = db_attach->priv;
- /* stealing dmabuf mutex to serialize map/unmap operations */
- struct mutex *lock = &db_attach->dmabuf->lock;
struct sg_table *sgt;
- mutex_lock(lock);
-
sgt = &attach->sgt;
/* return previously mapped sg table */
- if (attach->dma_dir == dma_dir) {
- mutex_unlock(lock);
+ if (attach->dma_dir == dma_dir)
return sgt;
- }
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
@@ -409,14 +403,11 @@ static struct sg_table *vb2_dc_dmabuf_ops_map(
if (dma_map_sgtable(db_attach->dev, sgt, dma_dir,
DMA_ATTR_SKIP_CPU_SYNC)) {
pr_err("failed to map scatterlist\n");
- mutex_unlock(lock);
return ERR_PTR(-EIO);
}
attach->dma_dir = dma_dir;
- mutex_unlock(lock);
-
return sgt;
}
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index 36ecdea8d707..36981a5b5c53 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -424,18 +424,12 @@ static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
{
struct vb2_dma_sg_attachment *attach = db_attach->priv;
- /* stealing dmabuf mutex to serialize map/unmap operations */
- struct mutex *lock = &db_attach->dmabuf->lock;
struct sg_table *sgt;
- mutex_lock(lock);
-
sgt = &attach->sgt;
/* return previously mapped sg table */
- if (attach->dma_dir == dma_dir) {
- mutex_unlock(lock);
+ if (attach->dma_dir == dma_dir)
return sgt;
- }
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
@@ -446,14 +440,11 @@ static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
/* mapping to the client with new direction */
if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
pr_err("failed to map scatterlist\n");
- mutex_unlock(lock);
return ERR_PTR(-EIO);
}
attach->dma_dir = dma_dir;
- mutex_unlock(lock);
-
return sgt;
}
diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
index 7831bf545874..41db707e43a4 100644
--- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
+++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
@@ -267,18 +267,12 @@ static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
{
struct vb2_vmalloc_attachment *attach = db_attach->priv;
- /* stealing dmabuf mutex to serialize map/unmap operations */
- struct mutex *lock = &db_attach->dmabuf->lock;
struct sg_table *sgt;
- mutex_lock(lock);
-
sgt = &attach->sgt;
/* return previously mapped sg table */
- if (attach->dma_dir == dma_dir) {
- mutex_unlock(lock);
+ if (attach->dma_dir == dma_dir)
return sgt;
- }
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
@@ -289,14 +283,11 @@ static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
/* mapping to the client with new direction */
if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
pr_err("failed to map scatterlist\n");
- mutex_unlock(lock);
return ERR_PTR(-EIO);
}
attach->dma_dir = dma_dir;
- mutex_unlock(lock);
-
return sgt;
}
--
2.37.3
On 9/28/22 22:15, Dmitry Osipenko wrote:
> Prepare InfiniBand drivers to the common dynamic dma-buf locking
> convention by starting to use the unlocked versions of dma-buf API
> functions.
>
> Acked-by: Christian König <[email protected]>
> Signed-off-by: Dmitry Osipenko <[email protected]>
> ---
> drivers/infiniband/core/umem_dmabuf.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
> index 04c04e6d24c3..43b26bc12288 100644
> --- a/drivers/infiniband/core/umem_dmabuf.c
> +++ b/drivers/infiniband/core/umem_dmabuf.c
> @@ -26,7 +26,8 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
> if (umem_dmabuf->sgt)
> goto wait_fence;
>
> - sgt = dma_buf_map_attachment(umem_dmabuf->attach, DMA_BIDIRECTIONAL);
> + sgt = dma_buf_map_attachment_unlocked(umem_dmabuf->attach,
> + DMA_BIDIRECTIONAL);
> if (IS_ERR(sgt))
> return PTR_ERR(sgt);
>
> @@ -102,8 +103,8 @@ void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
> umem_dmabuf->last_sg_trim = 0;
> }
>
> - dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
> - DMA_BIDIRECTIONAL);
> + dma_buf_unmap_attachment_unlocked(umem_dmabuf->attach, umem_dmabuf->sgt,
> + DMA_BIDIRECTIONAL);
>
> umem_dmabuf->sgt = NULL;
> }
Jason / Leon,
Could you please ack this patch?
--
Best regards,
Dmitry
On Sun, Oct 09, 2022 at 03:08:56AM +0300, Dmitry Osipenko wrote:
> On 9/28/22 22:15, Dmitry Osipenko wrote:
> > Prepare InfiniBand drivers to the common dynamic dma-buf locking
> > convention by starting to use the unlocked versions of dma-buf API
> > functions.
> >
> > Acked-by: Christian König <[email protected]>
> > Signed-off-by: Dmitry Osipenko <[email protected]>
> > ---
> > drivers/infiniband/core/umem_dmabuf.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
> > index 04c04e6d24c3..43b26bc12288 100644
> > --- a/drivers/infiniband/core/umem_dmabuf.c
> > +++ b/drivers/infiniband/core/umem_dmabuf.c
> > @@ -26,7 +26,8 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
> > if (umem_dmabuf->sgt)
> > goto wait_fence;
> >
> > - sgt = dma_buf_map_attachment(umem_dmabuf->attach, DMA_BIDIRECTIONAL);
> > + sgt = dma_buf_map_attachment_unlocked(umem_dmabuf->attach,
> > + DMA_BIDIRECTIONAL);
> > if (IS_ERR(sgt))
> > return PTR_ERR(sgt);
> >
> > @@ -102,8 +103,8 @@ void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
> > umem_dmabuf->last_sg_trim = 0;
> > }
> >
> > - dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
> > - DMA_BIDIRECTIONAL);
> > + dma_buf_unmap_attachment_unlocked(umem_dmabuf->attach, umem_dmabuf->sgt,
> > + DMA_BIDIRECTIONAL);
> >
> > umem_dmabuf->sgt = NULL;
> > }
>
> Jason / Leon,
>
> Could you please ack this patch?
You probably don't need it, for something so simple, but sure
Acked-by: Jason Gunthorpe <[email protected]>
Jason
On 9/28/22 22:15, Dmitry Osipenko wrote:
> Hello,
>
> This series moves all drivers to a dynamic dma-buf locking specification.
> From now on all dma-buf importers are made responsible for holding
> dma-buf's reservation lock around all operations performed over dma-bufs
> in accordance to the locking specification. This allows us to utilize
> reservation lock more broadly around kernel without fearing of a potential
> deadlocks.
>
> This patchset passes all i915 selftests. It was also tested using VirtIO,
> Panfrost, Lima, Tegra, udmabuf, AMDGPU and Nouveau drivers. I tested cases
> of display+GPU, display+V4L and GPU+V4L dma-buf sharing (where appropriate),
> which covers majority of kernel drivers since rest of the drivers share
> same or similar code paths.
All the non-drm patches have been acked by the respective maintainers.
I'm now feeling comfortable to take this series into drm-misc-next and
going to do it later this week.
If anyone have more comments to add, then please do it now. It won't be
possible to drop out patches from drm-misc once they will be merged. All
further changes will have to be made on top of the applied patches.
Thanks to all who reviewed this patchset!
--
Best regards,
Dmitry