linux-kernel - [PATCH AUTOSEL 4.19 088/206] dmaengine: stm32-dma: use vchan_terminate_vdesc() in .terminate

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Message-Id: <20200918020802.2065198-88-sashal@kernel.org>
Date:   Thu, 17 Sep 2020 22:06:04 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Amelie Delaunay <amelie.delaunay@...com>,
        Vinod Koul <vkoul@...nel.org>, Sasha Levin <sashal@...nel.org>,
        dmaengine@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH AUTOSEL 4.19 088/206] dmaengine: stm32-dma: use vchan_terminate_vdesc() in .terminate_all

From: Amelie Delaunay <amelie.delaunay@...com>

[ Upstream commit d80cbef35bf89b763f06e03bb4ff8f933bf012c5 ]

To avoid race with vchan_complete, use the race free way to terminate
running transfer.

Move vdesc->node list_del in stm32_dma_start_transfer instead of in
stm32_mdma_chan_complete to avoid another race in vchan_dma_desc_free_list.

Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
Link: https://lore.kernel.org/r/20200129153628.29329-9-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/dma/stm32-dma.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 4903a408fc146..ac7af440f8658 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -494,8 +494,10 @@ static int stm32_dma_terminate_all(struct dma_chan *c)
 
 	spin_lock_irqsave(&chan->vchan.lock, flags);
 
-	if (chan->busy) {
-		stm32_dma_stop(chan);
+	if (chan->desc) {
+		vchan_terminate_vdesc(&chan->desc->vdesc);
+		if (chan->busy)
+			stm32_dma_stop(chan);
 		chan->desc = NULL;
 	}
 
@@ -551,6 +553,8 @@ static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
 		if (!vdesc)
 			return;
 
+		list_del(&vdesc->node);
+
 		chan->desc = to_stm32_dma_desc(vdesc);
 		chan->next_sg = 0;
 	}
@@ -628,7 +632,6 @@ static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan)
 		} else {
 			chan->busy = false;
 			if (chan->next_sg == chan->desc->num_sgs) {
-				list_del(&chan->desc->vdesc.node);
 				vchan_cookie_complete(&chan->desc->vdesc);
 				chan->desc = NULL;
 			}
-- 
2.25.1