dmaengine: fix dmaengine_unmap failure

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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Xuelin Shi <xuelin.shi@freescale.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index a886713..d5d30ed 100644 (file)
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1009,6 +1009,7 @@ static void dmaengine_unmap(struct kref *kref)
                dma_unmap_page(dev, unmap->addr[i], unmap->len,
                               DMA_BIDIRECTIONAL);
        }
+       cnt = unmap->map_cnt;
        mempool_free(unmap, __get_unmap_pool(cnt)->pool);
 }
 
@@ -1074,6 +1075,7 @@ dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
        memset(unmap, 0, sizeof(*unmap));
        kref_init(&unmap->kref);
        unmap->dev = dev;
+       unmap->map_cnt = nr;
 
        return unmap;
 }

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 8300fb8..72cb0dd 100644 (file)
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -429,6 +429,7 @@ typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param);
 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;