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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-11-14 17:27:19 +0100 |
|---|---|---|
| committer | Sumit Semwal <sumit.semwal@linaro.org> | 2017-11-21 18:07:05 +0100 |
| commit | 03e4e0a9e02cf703da331ff6cfd57d0be9bf5692 (patch) | |
| tree | dc27892dd1af53bf9d6f5f1925762e7b8286f992 /drivers/base | |
| parent | Merge airlied/drm-next into drm-misc-next (diff) | |
| download | linux-03e4e0a9e02cf703da331ff6cfd57d0be9bf5692.tar.xz linux-03e4e0a9e02cf703da331ff6cfd57d0be9bf5692.zip | |
dma-buf/fence: Fix lock inversion within dma-fence-array
Ages ago Rob Clark noted,
"Currently with fence-array, we have a potential deadlock situation. If
we fence_add_callback() on an array-fence, the array-fence's lock is
acquired first, and in it's ->enable_signaling() callback, it will install
cbs on it's array-member fences, so the array-member's lock is acquired
second.
But in the signal path, the array-member's lock is acquired first, and
the array-fence's lock acquired second."
Rob proposed either extensive changes to dma-fence to unnest the
fence-array signaling, or to defer the signaling onto a workqueue. This
is a more refined version of the later, that should keep the latency
of the fence signaling to a minimum by using an irq-work, which is
executed asap.
Reported-by: Rob Clark <robdclark@gmail.com>
Suggested-by: Rob Clark <robdclark@gmail.com>
References: 1476635975-21981-1-git-send-email-robdclark@gmail.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Christian König <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20171114162719.30958-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 1a5f6a157a57..62b0de06836e 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -244,6 +244,7 @@ config DMA_SHARED_BUFFER bool default n select ANON_INODES + select IRQ_WORK help This option enables the framework for buffer-sharing between multiple drivers. A buffer is associated with a file using driver |