3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xuelin Shi <[email protected]>

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 <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 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;


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