[PATCH v2 0/2] Added few improvement and fixes.

[PATCH v2 0/2] Added few improvement and fixes.

[Sanjay R Mehta]

From: Sanjay R Mehta <sanju.mehta@amd.com>

This patch series fixes a concurrency issue with DMA transfer and
descriptor handling with a graceful exit.

Sanjay R Mehta (2):
  dmaengine: ptdma: fix concurrency issue with multiple dma transfer
  dmaengine: ptdma: handle the cases based on DMA is complete

 drivers/dma/ptdma/ptdma-dmaengine.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

-- 
2.7.4

[PATCH v2 1/2] dmaengine: ptdma: fix concurrency issue with multiple dma transfer

[Sanjay R Mehta]

From: Sanjay R Mehta <sanju.mehta@amd.com>

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>
---
 drivers/dma/ptdma/ptdma-dmaengine.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/ptdma/ptdma-dmaengine.c b/drivers/dma/ptdma/ptdma-dmaengine.c
index c9e52f6..e38dca4 100644
--- 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_chan *dma_chan)
 	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_chan *dma_chan)
 	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);
 }
 
-- 
2.7.4

[PATCH v2 2/2] dmaengine: ptdma: handle the cases based on DMA is complete

[Sanjay R Mehta]

From: Sanjay R Mehta <sanju.mehta@amd.com>

There is a need to segregate the cases when DMA is complete or not.
In case if DMA is already complete there is no need to handle it
again and gracefully exit from the function.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
---
 drivers/dma/ptdma/ptdma-dmaengine.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/ptdma/ptdma-dmaengine.c b/drivers/dma/ptdma/ptdma-dmaengine.c
index e38dca4..91b93e8 100644
--- a/drivers/dma/ptdma/ptdma-dmaengine.c
+++ b/drivers/dma/ptdma/ptdma-dmaengine.c
@@ -100,12 +100,17 @@ static struct pt_dma_desc *pt_handle_active_desc(struct pt_dma_chan *chan,
 		spin_lock_irqsave(&chan->vc.lock, flags);
 
 		if (desc) {
-			if (desc->status != DMA_ERROR)
-				desc->status = DMA_COMPLETE;
-
-			dma_cookie_complete(tx_desc);
-			dma_descriptor_unmap(tx_desc);
-			list_del(&desc->vd.node);
+			if (desc->status != DMA_COMPLETE) {
+				if (desc->status != DMA_ERROR)
+					desc->status = DMA_COMPLETE;
+
+				dma_cookie_complete(tx_desc);
+				dma_descriptor_unmap(tx_desc);
+				list_del(&desc->vd.node);
+			} else {
+				/* Don't handle it twice */
+				tx_desc = NULL;
+			}
 		}
 
 		desc = pt_next_dma_desc(chan);
-- 
2.7.4

Re: [PATCH v2 0/2] Added few improvement and fixes.

[Vinod Koul]

On 02-02-22, 09:14, Sanjay R Mehta wrote:
> From: Sanjay R Mehta <sanju.mehta@amd.com>
> 
> This patch series fixes a concurrency issue with DMA transfer and
> descriptor handling with a graceful exit.

Applied, thanks

-- 
~Vinod