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authorChris Wilson <chris@chris-wilson.co.uk>2017-11-14 16:27:19 +0000
committerSumit Semwal <sumit.semwal@linaro.org>2017-11-21 22:37:05 +0530
commit03e4e0a9e02cf703da331ff6cfd57d0be9bf5692 (patch)
treedc27892dd1af53bf9d6f5f1925762e7b8286f992 /drivers/base/Kconfig
parent70c5f93669249886b151812076509f30569aff80 (diff)
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/Kconfig')
-rw-r--r--drivers/base/Kconfig1
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