From: Dave Jiang <dave.jiang@xxxxxxxxx> [ Upstream commit 673d812d30be67942762bb9e8548abb26a3ba4a7 ] The sbitmap wait and allocate routine checks the index that is returned from sbitmap_queue_get(). It should be idxd >= 0 as 0 is also a valid index. This fixes issue where submission path hangs when WQ size is 1. Fixes: 0705107fcc80 ("dmaengine: idxd: move submission to sbitmap_queue") Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> Link: https://lore.kernel.org/r/162697645067.3478714.506720687816951762.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/dma/idxd/submit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c index 36c9c1a89b7e..196d6cf11965 100644 --- a/drivers/dma/idxd/submit.c +++ b/drivers/dma/idxd/submit.c @@ -67,7 +67,7 @@ struct idxd_desc *idxd_alloc_desc(struct idxd_wq *wq, enum idxd_op_type optype) if (signal_pending_state(TASK_INTERRUPTIBLE, current)) break; idx = sbitmap_queue_get(sbq, &cpu); - if (idx > 0) + if (idx >= 0) break; schedule(); } -- 2.33.0