[RFC 2/4] dma-fence: Slightly safer dma_fence_set_deadline

[Tvrtko Ursulin]

Similar to the previous patch lets precede the fence->ops dereference with
the signaled check. This reduces the window to hit the race where sync
file can get into a signaled DRM scheduler fence which was left "dangling"
after the driver had potentially torn down the corresponding internal
state.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
Cc: Christian König <christian.koenig at amd.com>
Cc: Danilo Krummrich <dakr at kernel.org>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: Philipp Stanner <phasta at kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/dma-buf/dma-fence.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index f0cdd3e99d36..b3f085a65910 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -968,7 +968,7 @@ EXPORT_SYMBOL(dma_fence_wait_any_timeout);
  */
 void dma_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
 {
-	if (fence->ops->set_deadline && !dma_fence_is_signaled(fence))
+	if (!dma_fence_is_signaled(fence) && fence->ops->set_deadline)
 		fence->ops->set_deadline(fence, deadline);
 }
 EXPORT_SYMBOL(dma_fence_set_deadline);
-- 
2.48.0