From: Sanjay R Mehta <sanju.mehta@amd.com>
Date: Wed, 2 Feb 2022 09:14:39 -0600
Subject: dmaengine: ptdma: fix concurrency issue with multiple dma transfer
Git-commit: 6fa7e0e836e23e2c758ac3930b040c8abbbf8a6f
Patch-mainline: 5.18-rc1
References: jsc#SLE-21315

The command should be submitted only if the engine is idle,
for this, the next available descriptor is checked and set the flag
to false in case the descriptor is non-empty.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1643814880-3882-2-git-send-email-Sanju.Mehta@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/dma/ptdma/ptdma-dmaengine.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/dma/ptdma/ptdma-dmaengine.c
+++ b/drivers/dma/ptdma/ptdma-dmaengine.c
@@ -233,9 +233,14 @@ static void pt_issue_pending(struct dma_
 	struct pt_dma_chan *chan = to_pt_chan(dma_chan);
 	struct pt_dma_desc *desc;
 	unsigned long flags;
+	bool engine_is_idle = true;
 
 	spin_lock_irqsave(&chan->vc.lock, flags);
 
+	desc = pt_next_dma_desc(chan);
+	if (desc)
+		engine_is_idle = false;
+
 	vchan_issue_pending(&chan->vc);
 
 	desc = pt_next_dma_desc(chan);
@@ -243,7 +248,7 @@ static void pt_issue_pending(struct dma_
 	spin_unlock_irqrestore(&chan->vc.lock, flags);
 
 	/* If there was nothing active, start processing */
-	if (desc)
+	if (engine_is_idle)
 		pt_cmd_callback(desc, 0);
 }