[PATCH 5.10 27/63] dmaengine: idxd: fix wq slot allocation index check

[Greg Kroah-Hartman]

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 417048e3c42a..0368c5490788 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -45,7 +45,7 @@ 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