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 chris@chris-wilson.co.uk Tested-by: Venkata Sandeep Dhanalakota venkata.s.dhanalakota@intel.com Reviewed-by: Venkata Sandeep Dhanalakota venkata.s.dhanalakota@intel.com --- 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 3d123502ff12..c435bbba851c 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.