[PATCH v5] dmaengine: sun6i-dma: Fix reclaim descriptors while terminating DMA

[PATCH v5] dmaengine: sun6i-dma: Fix reclaim descriptors while terminating DMA

[Hongling Zeng]

When terminating DMA transfers, active descriptors are not properly
reclaimed. Only cyclic descriptors were handled, leaving non-cyclic
descriptors and their LLI chains to be permanently leaked.

Fix by using vchan_terminate_vdesc() which handles both cyclic and
non-cyclic descriptors by adding them to desc_terminated queue for
proper cleanup.

Add pchan->desc != pchan->done check to prevent double-adding completed
descriptors, which would corrupt the list.

Fixes: 555859308723 ("dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller")
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Suggested-by: Frank Li <Frank.li@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>

---
 Change in v2;
 -Add pchan->desc != pchan->done check to prevent race condition
  where completed descriptors could be double-added to desc_completed
  list, causing list corruption
---
 Change in v3:
 -Fix by using vchan_terminate_vdesc() as suggested by Frank Li
---
 Change in v4:
 -Correct the commit message
---
 Chaneg in v5:
 -Correct the subject
 -Add reviewed-by
---
 drivers/dma/sun6i-dma.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index 7a79f346250a..134ae840f176 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -946,16 +946,13 @@ static int sun6i_dma_terminate_all(struct dma_chan *chan)
 
 	spin_lock_irqsave(&vchan->vc.lock, flags);
 
-	if (vchan->cyclic) {
-		vchan->cyclic = false;
-		if (pchan && pchan->desc) {
-			struct virt_dma_desc *vd = &pchan->desc->vd;
-			struct virt_dma_chan *vc = &vchan->vc;
-
-			list_add_tail(&vd->node, &vc->desc_completed);
-		}
+	if (pchan && pchan->desc && pchan->desc != pchan->done) {
+		struct virt_dma_desc *vd = &pchan->desc->vd;
+		
+		vchan_terminate_vdesc(vd);
 	}
 
+	vchan->cyclic = false;
 	vchan_get_all_descriptors(&vchan->vc, &head);
 
 	if (pchan) {
-- 
2.25.1

Re: [PATCH v5] dmaengine: sun6i-dma: Fix reclaim descriptors while terminating DMA

[Vinod Koul]

On 01-07-26, 12:57, Hongling Zeng wrote:
> When terminating DMA transfers, active descriptors are not properly
> reclaimed. Only cyclic descriptors were handled, leaving non-cyclic
> descriptors and their LLI chains to be permanently leaked.
> 
> Fix by using vchan_terminate_vdesc() which handles both cyclic and
> non-cyclic descriptors by adding them to desc_terminated queue for
> proper cleanup.
> 
> Add pchan->desc != pchan->done check to prevent double-adding completed
> descriptors, which would corrupt the list.

You should run checkpatch to fix the formatting issues.
ERROR: trailing whitespace
#65: FILE: drivers/dma/sun6i-dma.c:95

For now, I have fixed and applied

-- 
~Vinod