kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.
Since its use in amdgpu/amdgpu_ttm.c is safe, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in amdgpu/amdgpu_ttm.c.
Suggested-by: Ira Weiny <ira.weiny(a)intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco(a)gmail.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 3b4c19412625..c11657b5915f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -2301,9 +2301,9 @@ static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
if (p->mapping != adev->mman.bdev.dev_mapping)
return -EPERM;
- ptr = kmap(p);
+ ptr = kmap_local_page(p);
r = copy_to_user(buf, ptr + off, bytes);
- kunmap(p);
+ kunmap_local(ptr);
if (r)
return -EFAULT;
@@ -2352,9 +2352,9 @@ static ssize_t amdgpu_iomem_write(struct file *f, const char __user *buf,
if (p->mapping != adev->mman.bdev.dev_mapping)
return -EPERM;
- ptr = kmap(p);
+ ptr = kmap_local_page(p);
r = copy_from_user(ptr + off, buf, bytes);
- kunmap(p);
+ kunmap_local(ptr);
if (r)
return -EFAULT;
--
2.37.1
Add a new ioctl called TEE_IOC_SHM_REGISTER_FD to register a
shared memory from a dmabuf file descriptor.
Etienne Carriere (1):
tee: new ioctl to a register tee_shm from a dmabuf file descriptor
drivers/tee/tee_core.c | 38 +++++++++++++++
drivers/tee/tee_shm.c | 99 +++++++++++++++++++++++++++++++++++++++-
include/linux/tee_drv.h | 11 +++++
include/uapi/linux/tee.h | 29 ++++++++++++
4 files changed, 175 insertions(+), 2 deletions(-)
--
2.25.0
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 and Tegra drivers. I tested cases of display+GPU,
display+V4L and GPU+V4L dma-buf sharing, which covers majority of kernel
drivers since rest of the drivers share same or similar code paths.
Changelog:
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 (5):
dma-buf: Add _unlocked postfix to function names
drm/gem: Take reservation lock for vmap/vunmap operations
dma-buf: Move all dma-bufs to dynamic locking specification
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 | 253 +++++++++++++-----
drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 4 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.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_cma_helper.c | 6 +-
drivers/gpu/drm/drm_gem_framebuffer_helper.c | 6 +-
drivers/gpu/drm/drm_gem_shmem_helper.c | 6 +-
drivers/gpu/drm/drm_prime.c | 12 +-
drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 6 +-
drivers/gpu/drm/exynos/exynos_drm_gem.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 14 +-
.../drm/i915/gem/selftests/i915_gem_dmabuf.c | 20 +-
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 8 +-
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 | 71 ++---
28 files changed, 372 insertions(+), 254 deletions(-)
--
2.36.1