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(-)
--
2.37.2
dma-buf has become a way to safely acquire a handle to non-struct page
memory that can still have lifetime controlled by the exporter. Notably
RDMA can now import dma-buf FDs and build them into MRs which allows for
PCI P2P operations. Extend this to allow vfio-pci to export MMIO memory
from PCI device BARs.
This series supports a use case for SPDK where a NVMe device will be owned
by SPDK through VFIO but interacting with a RDMA device. The RDMA device
may directly access the NVMe CMB or directly manipulate the NVMe device's
doorbell using PCI P2P.
However, as a general mechanism, it can support many other scenarios with
VFIO. I imagine this dmabuf approach to be usable by iommufd as well for
generic and safe P2P mappings.
This series goes after the "Break up ioctl dispatch functions to one
function per ioctl" series.
This is on github: https://github.com/jgunthorpe/linux/commits/vfio_dma_buf
Jason Gunthorpe (4):
dma-buf: Add dma_buf_try_get()
vfio: Add vfio_device_get()
vfio_pci: Do not open code pci_try_reset_function()
vfio/pci: Allow MMIO regions to be exported through dma-buf
drivers/vfio/pci/Makefile | 1 +
drivers/vfio/pci/vfio_pci_config.c | 22 ++-
drivers/vfio/pci/vfio_pci_core.c | 33 +++-
drivers/vfio/pci/vfio_pci_dma_buf.c | 265 ++++++++++++++++++++++++++++
drivers/vfio/pci/vfio_pci_priv.h | 24 +++
drivers/vfio/vfio_main.c | 3 +-
include/linux/dma-buf.h | 13 ++
include/linux/vfio.h | 6 +
include/linux/vfio_pci_core.h | 1 +
include/uapi/linux/vfio.h | 18 ++
10 files changed, 364 insertions(+), 22 deletions(-)
create mode 100644 drivers/vfio/pci/vfio_pci_dma_buf.c
base-commit: 385f0411fcd2780b5273992832cdc8edcd5b8ea9
--
2.37.2
Hi oushixiong,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on drm/drm-next drm-intel/for-linux-next drm-tip/drm-tip linus/master v6.0-rc3 next-20220826]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/oushixiong/drm-ast-add-dmabu…
base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
config: i386-randconfig-a013 (https://download.01.org/0day-ci/archive/20220829/202208291132.RQqpjzO1-lkp@…)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/da31884b8b7e33af5cd8aa750dea3…
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review oushixiong/drm-ast-add-dmabuf-prime-buffer-sharing-support/20220829-084713
git checkout da31884b8b7e33af5cd8aa750dea30fde59d52aa
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/gpu/drm/ast/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>):
>> drivers/gpu/drm/ast/ast_drv.c:54:24: warning: no previous prototype for function 'ast_gem_prime_import' [-Wmissing-prototypes]
struct drm_gem_object *ast_gem_prime_import(struct drm_device *dev,
^
drivers/gpu/drm/ast/ast_drv.c:54:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
struct drm_gem_object *ast_gem_prime_import(struct drm_device *dev,
^
static
1 warning generated.
vim +/ast_gem_prime_import +54 drivers/gpu/drm/ast/ast_drv.c
53
> 54 struct drm_gem_object *ast_gem_prime_import(struct drm_device *dev,
55 struct dma_buf *dma_buf)
56 {
57 struct drm_gem_vram_object *gbo;
58
59 gbo = drm_gem_vram_of_gem(dma_buf->priv);
60 if (gbo->bo.base.dev == dev) {
61 /*
62 * Importing dmabuf exported from out own gem increases
63 * refcount on gem itself instead of f_count of dmabuf.
64 */
65 drm_gem_object_get(&gbo->bo.base);
66 return &gbo->bo.base;
67 }
68
69 gbo = drm_gem_vram_create(dev, dma_buf->size, 0);
70 if (IS_ERR(gbo))
71 return NULL;
72
73 get_dma_buf(dma_buf);
74 return &gbo->bo.base;
75 }
76
--
0-DAY CI Kernel Test Service
https://01.org/lkp