From 5de376bb434f80a13138f0ebedc8351ab73d8b0d Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 9 Apr 2020 12:01:00 +0100 Subject: [PATCH] dma-buf: Report signaled links inside dma-fence-chain Whenever we walk along the dma-fence-chain, we prune signaled links to keep the chain nice and tidy. This leads to situations where we can prune a link and report the earlier fence as the target seqno -- violating our own consistency checks that the seqno is not more advanced than the last element in a dma-fence-chain. Report a NULL fence and success if the seqno has already been signaled. Signed-off-by: Chris Wilson Tested-by: Venkata Sandeep Dhanalakota Reviewed-by: Venkata Sandeep Dhanalakota Link: https://patchwork.freedesktop.org/patch/msgid/20200409110101.18400-2-chris@chris-wilson.co.uk --- drivers/dma-buf/dma-fence-chain.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c index 3d12350..c435bbb 100644 --- a/drivers/dma-buf/dma-fence-chain.c +++ b/drivers/dma-buf/dma-fence-chain.c @@ -99,6 +99,12 @@ int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno) return -EINVAL; dma_fence_chain_for_each(*pfence, &chain->base) { + if ((*pfence)->seqno < seqno) { /* already signaled */ + dma_fence_put(*pfence); + *pfence = NULL; + break; + } + if ((*pfence)->context != chain->base.context || to_dma_fence_chain(*pfence)->prev_seqno < seqno) break; @@ -222,6 +228,7 @@ EXPORT_SYMBOL(dma_fence_chain_ops); * @chain: the chain node to initialize * @prev: the previous fence * @fence: the current fence + * @seqno: the sequence number (syncpt) of the fence within the chain * * Initialize a new chain node and either start a new chain or add the node to * the existing chain of the previous fence. -- 2.7.4