linux-kernel - [PATCH 8/8] dmaengine: stm32-dma: use vchan_terminate_vdesc() in .terminate

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Date:   Wed, 29 Jan 2020 16:36:28 +0100
From:   Amelie Delaunay <amelie.delaunay@...com>
To:     Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>
CC:     <dmaengine@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Amelie Delaunay <amelie.delaunay@...com>,
        Pierre-Yves MORDRET <pierre-yves.mordret@...com>
Subject: [PATCH 8/8] dmaengine: stm32-dma: use vchan_terminate_vdesc() in .terminate_all

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>
---
 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 b585e11c2168..0ddbaa4b4f0b 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -478,8 +478,10 @@ 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;
 	}
 
@@ -535,6 +537,8 @@ 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;
 	}
@@ -613,7 +617,6 @@ 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;
 			}
-- 
2.17.1