path: root/include
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authorChristian König <christian.koenig@amd.com>2017-09-15 11:53:07 +0200
committerAlex Deucher <alexander.deucher@amd.com>2017-10-09 11:14:05 -0400
commitf8e0731db4a02c8c5624e1dce6dc983210a51f64 (patch)
tree0744c2447a9c5f68e3953b8b1bd90abedc65bfdf /include
parent39e16ba16c147e662bf9fbcee9a99d70d420382f (diff)
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')
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

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