[PATCH 3.14 190/228] dmaengine: fix dmaengine_unmap failure

Greg Kroah-Hartman
2014-06-05T00:03:16Z

From: Xuelin Shi <xuelin.shi@freescale.com>

commit c1f43dd9c20d85e66c4d77e284f64ac114abe3f8 upstream.

The count which is used to get_unmap_data maybe not the same as the
count computed in dmaengine_unmap which causes to free data in a
wrong pool.

This patch fixes this issue by keeping the map count with unmap_data
structure and use this count to get the pool.

Signed-off-by: Xuelin Shi <xuelin.shi@freescale.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/dma/dmaengine.c | 2 ++
include/linux/dmaengine.h | 1 +
2 files changed, 3 insertions(+)

--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1014,6 +1014,7 @@ static void dmaengine_unmap(struct kref
dma_unmap_page(dev, unmap->addr[i], unmap->len,
DMA_BIDIRECTIONAL);
}
+ cnt = unmap->map_cnt;
mempool_free(unmap, __get_unmap_pool(cnt)->pool);
}

@@ -1079,6 +1080,7 @@ dmaengine_get_unmap_data(struct device *
memset(unmap, 0, sizeof(*unmap));
kref_init(&unmap->kref);
unmap->dev = dev;
+ unmap->map_cnt = nr;

return unmap;
}
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -433,6 +433,7 @@ typedef bool (*dma_filter_fn)(struct dma
typedef void (*dma_async_tx_callback)(void *dma_async_param);

struct dmaengine_unmap_data {
+ u8 map_cnt;
u8 to_cnt;
u8 from_cnt;
u8 bidi_cnt;