On 1/20/22 14:27, Christian König wrote:
Chaining of dma_fence_chain objects is only allowed through the prev
fence and not through the contained fence.
Warn about that when we create a dma_fence_chain.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/dma-buf/dma-fence-chain.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c
index 1b4cb3e5cec9..fa33f6b7f77b 100644
--- a/drivers/dma-buf/dma-fence-chain.c
+++ b/drivers/dma-buf/dma-fence-chain.c
@@ -254,5 +254,13 @@ void dma_fence_chain_init(struct dma_fence_chain *chain,
dma_fence_init(&chain->base, &dma_fence_chain_ops,
&chain->lock, context, seqno);
+
+ /* Chaining dma_fence_chain container together is only allowed through
Nit: Multi-line comment.
Otherwise, Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
+ * the prev fence and not through the contained fence.
+ *
+ * The correct way of handling this is to flatten out the fence
+ * structure into a dma_fence_array by the caller instead.
+ */
+ WARN_ON(dma_fence_is_chain(fence));
}
EXPORT_SYMBOL(dma_fence_chain_init);
