dmaengine: stm32-dma: use vchan_terminate_vdesc() in .terminate_all

[ Upstream commit d80cbef3 ]

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@st.com>
Link: https://lore.kernel.org/r/20200129153628.29329-9-amelie.delaunay@st.comSigned-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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;
 			}