dma-buf/fence: don't wait when specified timeout is zero

When specified timeout is zero for fence_wait_timeout, just check if the fence
is signaled or not without wait.

Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-By: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

drivers/dma-buf/fence.c

@@ -159,6 +159,9 @@ fence_wait_timeout(struct fence *fence, bool intr, signed long timeout)
 	if (WARN_ON(timeout < 0))
 		return -EINVAL;
 
+	if (timeout == 0)
+		return fence_is_signaled(fence);
+
 	trace_fence_wait_start(fence);
 	ret = fence->ops->wait(fence, intr, timeout);
 	trace_fence_wait_end(fence);