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

BugLink: https://bugs.launchpad.net/bugs/1900624
[ 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@st.com>
Link: https://lore.kernel.org/r/20200129153628.29329-9-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>

diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 5989b08935211537026f289a0b1eb5bc320b4284..6c5771de32c679f50dedb522cb7d0a91689445f4 100644 (file)
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -488,8 +488,10 @@ 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;
        }
 
@@ -545,6 +547,8 @@ 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;
        }
@@ -622,7 +626,6 @@ 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;
                        }