msm: kgsl: Don't try to wait for fences that have been signaled

Trying to wait for fences that have already been signaled incurs a high
setup cost, since dynamic memory allocation must be used. Avoiding this
overhead when it isn't needed improves performance.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>

drivers/gpu/msm/kgsl_sync.c

@@ -407,6 +407,11 @@ struct kgsl_sync_fence_cb *kgsl_sync_fence_async_wait(int fd,
 	if (fence == NULL)
 		return ERR_PTR(-EINVAL);
 
+	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
+		dma_fence_put(fence);
+		return NULL;
+	}
+
 	/* create the callback */
 	kcb = kzalloc(sizeof(*kcb), GFP_ATOMIC);
 	if (kcb == NULL) {