linux-kernel - [PATCH 4.19 085/245] dmaengine: stm32-mdma: use vchan_terminate_vdesc() in .terminate

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Date:   Tue, 29 Sep 2020 12:58:56 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Amelie Delaunay <amelie.delaunay@...com>,
        Vinod Koul <vkoul@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 085/245] dmaengine: stm32-mdma: use vchan_terminate_vdesc() in .terminate_all

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

[ Upstream commit dfc708812a2acfc0ca56f56233b3c3e7b0d4ffe7 ]

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

Move vdesc->node list_del in stm32_mdma_start_transfer instead of in
stm32_mdma_xfer_end to avoid another race in vchan_dma_desc_free_list.

Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
Link: https://lore.kernel.org/r/20200127085334.13163-7-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/dma/stm32-mdma.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index 8c3c3e5b812a8..9c6867916e890 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -1137,6 +1137,8 @@ static void stm32_mdma_start_transfer(struct stm32_mdma_chan *chan)
 		return;
 	}
 
+	list_del(&vdesc->node);
+
 	chan->desc = to_stm32_mdma_desc(vdesc);
 	hwdesc = chan->desc->node[0].hwdesc;
 	chan->curr_hwdesc = 0;
@@ -1252,8 +1254,10 @@ static int stm32_mdma_terminate_all(struct dma_chan *c)
 	LIST_HEAD(head);
 
 	spin_lock_irqsave(&chan->vchan.lock, flags);
-	if (chan->busy) {
-		stm32_mdma_stop(chan);
+	if (chan->desc) {
+		vchan_terminate_vdesc(&chan->desc->vdesc);
+		if (chan->busy)
+			stm32_mdma_stop(chan);
 		chan->desc = NULL;
 	}
 	vchan_get_all_descriptors(&chan->vchan, &head);
@@ -1341,7 +1345,6 @@ static enum dma_status stm32_mdma_tx_status(struct dma_chan *c,
 
 static void stm32_mdma_xfer_end(struct stm32_mdma_chan *chan)
 {
-	list_del(&chan->desc->vdesc.node);
 	vchan_cookie_complete(&chan->desc->vdesc);
 	chan->desc = NULL;
 	chan->busy = false;
-- 
2.25.1