[PATCH 5/6] dmaengine: plx_dma: use spin_lock_bh() in plx_dma_process_desc()

[Logan Gunthorpe]

plx_dma_process_desc() is also called from plx_dma_tx_status() in
process context. With a plain spin_lock(), the desc_task tasklet can
run on the same CPU while the lock is held, and spin on it forever.

Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Link: https://lore.kernel.org/dmaengine/20260717223217.B6FBF1F000E9@xxxxxxxxxxxxxxx
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
---
 drivers/dma/plx_dma.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/plx_dma.c b/drivers/dma/plx_dma.c
index e4243b66f933..8c4b19d681ad 100644
--- a/drivers/dma/plx_dma.c
+++ b/drivers/dma/plx_dma.c
@@ -138,7 +138,7 @@ static void plx_dma_process_desc(struct plx_dma_dev *plxdev)
 	struct plx_dma_desc *desc;
 	u32 flags;
 
-	spin_lock(&plxdev->ring_lock);
+	spin_lock_bh(&plxdev->ring_lock);
 
 	while (plxdev->tail != plxdev->head) {
 		desc = plx_dma_get_desc(plxdev, plxdev->tail);
@@ -172,7 +172,7 @@ static void plx_dma_process_desc(struct plx_dma_dev *plxdev)
 		plxdev->tail++;
 	}
 
-	spin_unlock(&plxdev->ring_lock);
+	spin_unlock_bh(&plxdev->ring_lock);
 }
 
 static void plx_dma_abort_desc(struct plx_dma_dev *plxdev)
-- 
2.47.3