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. v2: fix comment style Signed-off-by: Christian König <christian.koenig@xxxxxxx> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> --- drivers/dma-buf/dma-fence-chain.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c index 1b4cb3e5cec9..084c6927b735 100644 --- a/drivers/dma-buf/dma-fence-chain.c +++ b/drivers/dma-buf/dma-fence-chain.c @@ -254,5 +254,14 @@ 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 + * 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); -- 2.25.1
