dma_fence_array: Fix PENDING_ERROR leak in dma_fence_array_signaled()

If a dma_fence_array is reported signaled by a call to
dma_fence_is_signaled(), it may leak the PENDING_ERROR status.

Fix this by clearing the PENDING_ERROR status if we return true in
dma_fence_array_signaled().

v2:
- Update Cc list, and add R-b.

Fixes: 1f70b8b ("dma-fence: Propagate errors to dma-fence-array container")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129152727.448908-1-thomas.hellstrom@linux.intel.com

drivers/dma-buf/dma-fence-array.c

@@ -104,7 +104,11 @@ static bool dma_fence_array_signaled(struct dma_fence *fence)
 {
 	struct dma_fence_array *array = to_dma_fence_array(fence);
 
-	return atomic_read(&array->num_pending) <= 0;
+	if (atomic_read(&array->num_pending) > 0)
+		return false;
+
+	dma_fence_array_clear_pending_error(array);
+	return true;
 }
 
 static void dma_fence_array_release(struct dma_fence *fence)