Merge tag 'dmaengine-fixes-3.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine

Pull dmaengine fixes from Dan Williams:
 "Two fixes for -stable:

   - async_mult() sometimes maps less buffers than initially requested.
      We end up freeing dmaengine_unmap_data on an invalid pool.

   - mv_xor: register write ordering fix"

* tag 'dmaengine-fixes-3.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine:
  dmaengine: fix dmaengine_unmap failure
  dma: mv_xor: Flush descriptors before activating a channel

3 files changed, 6 insertions, 5 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index a886713937fd..d5d30ed863ce 100644
--- 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/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index 766b68ed505c..394cbc5c93e3 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -191,12 +191,10 @@ static void mv_set_mode(struct mv_xor_chan *chan,
 
 static void mv_chan_activate(struct mv_xor_chan *chan)
 {
-        u32 activation;
-
         dev_dbg(mv_chan_to_devp(chan), " activate chan.\n");
-        activation = readl_relaxed(XOR_ACTIVATION(chan));
-        activation |= 0x1;
-        writel_relaxed(activation, XOR_ACTIVATION(chan));
+
+        /* writel ensures all descriptors are flushed before activation */
+        writel(BIT(0), XOR_ACTIVATION(chan));
 }
 
 static char mv_chan_is_busy(struct mv_xor_chan *chan)
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 8300fb87b84a..72cb0ddb9678 100644
--- 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;