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:
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 (9): dma-buf: Add _unlocked postfix to function names dma-buf: Add locked variant of dma_buf_vmap/vunmap() drm/gem: Take reservation lock for vmap/vunmap operations dma-buf: Move dma_buf_vmap/vunmap_unlocked() to dynamic locking specification dma-buf: Move dma_buf_mmap_unlocked() to dynamic locking specification dma-buf: Move dma-buf attachment to dynamic locking specification dma-buf: Document dynamic locking convention media: videobuf2: Stop using internal dma-buf lock dma-buf: Remove internal lock
Documentation/driver-api/dma-buf.rst | 6 + drivers/dma-buf/dma-buf.c | 276 ++++++++++++++---- drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 4 +- drivers/gpu/drm/armada/armada_gem.c | 14 +- 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_shmem_helper.c | 2 +- drivers/gpu/drm/drm_gem_ttm_helper.c | 9 +- drivers/gpu/drm/drm_prime.c | 12 +- drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 4 +- drivers/gpu/drm/exynos/exynos_drm_gem.c | 2 +- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 6 +- drivers/gpu/drm/i915/gem/i915_gem_object.c | 12 + .../drm/i915/gem/selftests/i915_gem_dmabuf.c | 20 +- drivers/gpu/drm/lima/lima_sched.c | 4 +- drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 8 +- 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 | 27 +- drivers/infiniband/core/umem_dmabuf.c | 11 +- .../common/videobuf2/videobuf2-dma-contig.c | 26 +- .../media/common/videobuf2/videobuf2-dma-sg.c | 23 +- .../common/videobuf2/videobuf2-vmalloc.c | 17 +- .../platform/nvidia/tegra-vde/dmabuf-cache.c | 12 +- drivers/misc/fastrpc.c | 12 +- drivers/xen/gntdev-dmabuf.c | 14 +- include/drm/drm_gem.h | 3 + include/linux/dma-buf.h | 57 ++-- 32 files changed, 410 insertions(+), 242 deletions(-)