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| author |   Christian König <christian.koenig@amd.com> | 2017-09-15 11:53:07 +0200 |
|---|---|---|
| committer |   Alex Deucher <alexander.deucher@amd.com> | 2017-10-09 11:14:05 -0400 |
| commit | f8e0731db4a02c8c5624e1dce6dc983210a51f64 (patch) | |
| tree | 0744c2447a9c5f68e3953b8b1bd90abedc65bfdf /include/linux/dma-fence.h | |
| parent | dma-buf: make reservation_object_copy_fences rcu save (diff) | |
| download | wireguard-linux-f8e0731db4a02c8c5624e1dce6dc983210a51f64.tar.xz wireguard-linux-f8e0731db4a02c8c5624e1dce6dc983210a51f64.zip | |
dma-fence: fix dma_fence_get_rcu_safe v2
When dma_fence_get_rcu() fails to acquire a reference it doesn't necessary
mean that there is no fence at all.
It usually mean that the fence was replaced by a new one and in this situation
we certainly want to have the new one as result and *NOT* NULL.
v2: Keep extra check after dma_fence_get_rcu().
Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1505469187-3565-1-git-send-email-deathsimple@vodafone.de
Diffstat (limited to 'include/linux/dma-fence.h')
| -rw-r--r-- | include/linux/dma-fence.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 171895072435..ca974224d92e 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -248,9 +248,12 @@ dma_fence_get_rcu_safe(struct dma_fence * __rcu *fencep) struct dma_fence *fence; fence = rcu_dereference(*fencep); - if (!fence || !dma_fence_get_rcu(fence)) + if (!fence) return NULL; + if (!dma_fence_get_rcu(fence)) + continue; + /* The atomic_inc_not_zero() inside dma_fence_get_rcu() * provides a full memory barrier upon success (such as now). * This is paired with the write barrier from assigning |