dmaengine: rcar-dmac: Fix oops due to unintialized list in error ISR

The error interrupt handler stops and reinitializes all channels. This
causes a crash for channels that have never been used, as their
descriptor lists are uninitialized. Fix it by initializing the
descriptor lists at probe time.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 5a6b85527107..2eb65e1bf938 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -929,11 +929,6 @@ static int rcar_dmac_alloc_chan_resources(struct dma_chan *chan)
         struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
         int ret;
 
-        INIT_LIST_HEAD(&rchan->desc.free);
-        INIT_LIST_HEAD(&rchan->desc.pending);
-        INIT_LIST_HEAD(&rchan->desc.active);
-        INIT_LIST_HEAD(&rchan->desc.done);
-        INIT_LIST_HEAD(&rchan->desc.wait);
         INIT_LIST_HEAD(&rchan->desc.chunks_free);
         INIT_LIST_HEAD(&rchan->desc.pages);
 
@@ -970,11 +965,11 @@ static void rcar_dmac_free_chan_resources(struct dma_chan *chan)
                 rchan->mid_rid = -EINVAL;
         }
 
-        list_splice(&rchan->desc.free, &list);
-        list_splice(&rchan->desc.pending, &list);
-        list_splice(&rchan->desc.active, &list);
-        list_splice(&rchan->desc.done, &list);
-        list_splice(&rchan->desc.wait, &list);
+        list_splice_init(&rchan->desc.free, &list);
+        list_splice_init(&rchan->desc.pending, &list);
+        list_splice_init(&rchan->desc.active, &list);
+        list_splice_init(&rchan->desc.done, &list);
+        list_splice_init(&rchan->desc.wait, &list);
 
         list_for_each_entry(desc, &list, node)
                 rcar_dmac_realloc_hwdesc(rchan, desc, 0);
@@ -1519,6 +1514,12 @@ static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
 
         spin_lock_init(&rchan->lock);
 
+        INIT_LIST_HEAD(&rchan->desc.free);
+        INIT_LIST_HEAD(&rchan->desc.pending);
+        INIT_LIST_HEAD(&rchan->desc.active);
+        INIT_LIST_HEAD(&rchan->desc.done);
+        INIT_LIST_HEAD(&rchan->desc.wait);
+
         /* Request the channel interrupt. */
         sprintf(pdev_irqname, "ch%u", index);
         irq = platform_get_irq_byname(pdev, pdev_irqname);