diff options
| author | Christian König <[email protected]> | 2017-09-15 11:53:07 +0200 |
|---|---|---|
| committer | Alex Deucher <[email protected]> | 2017-10-09 11:14:05 -0400 |
| commit | f8e0731db4a02c8c5624e1dce6dc983210a51f64 (patch) | |
| tree | 0744c2447a9c5f68e3953b8b1bd90abedc65bfdf | |
| parent | 39e16ba16c147e662bf9fbcee9a99d70d420382f (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 <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Maarten Lankhorst <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
| -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 |