[PATCH 2/3] dmaengine: rcar-dmac: Add missing dma_descriptor_unmap()

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

From: Koichiro Den <den@valinux.co.jp>

Call dma_descriptor_unmap() right after dma_cookie_complete() in the
threaded IRQ completion path. Without this, streaming DMA mappings
attached to the descriptor are never released and may eventually exhaust
DMA mapping resources (e.g. IOVA with an IOMMU or bounce-buffer slots
with SWIOTLB), leading to dma_map_* failures.

Also ensure dma_descriptor_unmap() is called in rcar_dmac_chan_reinit()
(error/terminate path) to avoid the same type of leaks.

Fixes: 87244fe5abdf ("dmaengine: rcar-dmac: Add Renesas R-Car Gen2 DMA Controller (DMAC) driver")
Signed-off-by: Koichiro Den <den@valinux.co.jp>
[wsa: added Fixes tag]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/dma/sh/rcar-dmac.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 5b54f1c4ce15..9155bceb723b 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -844,6 +844,7 @@ static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
 
 	list_for_each_entry_safe(desc, _desc, &descs, node) {
 		list_del(&desc->node);
+		dma_descriptor_unmap(&desc->async_tx);
 		rcar_dmac_desc_put(chan, desc);
 	}
 }
@@ -1654,6 +1655,7 @@ static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev)
 		desc = list_first_entry(&chan->desc.done, struct rcar_dmac_desc,
 					node);
 		dma_cookie_complete(&desc->async_tx);
+		dma_descriptor_unmap(&desc->async_tx);
 		list_del(&desc->node);
 
 		dmaengine_desc_get_callback(&desc->async_tx, &cb);
-- 
2.53.0