[PATCH 1/4] dmaengine: ste_dma40: Fix failed start cleanup

[Linus Walleij <linusw@kernel.org>]

If d40_start() fails after a queued descriptor has been moved to the
active list, d40_queue_start() currently returns NULL without unwinding
the descriptor state or clearing the channel busy flag.

Fix this pre-existing error path by removing and freeing the descriptor,
clearing the busy flag and returning the error pointer to distinguish the
failure from the no-work case.

Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/dmaengine/20260618051539.15E201F000E9@smtp.kernel.org/
Assisted-by: Codex:gpt-5-5
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
 drivers/dma/ste_dma40.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 0d9ffa3e2663..d5837aa0a789 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -1531,8 +1531,12 @@ static struct d40_desc *d40_queue_start(struct d40_chan *d40c)
 		/* Start dma job */
 		err = d40_start(d40c);
 
-		if (err)
-			return NULL;
+		if (err) {
+			d40_desc_remove(d40d);
+			d40_desc_free(d40c, d40d);
+			d40c->busy = false;
+			return ERR_PTR(err);
+		}
 	}
 
 	return d40d;

-- 
2.55.0