diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index a886713937fd05b38fc10866bbce5266ac0bfae1..d5d30ed863ceb904c6e19e245b94d7ddba40f88f 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 766b68ed505c4d2b3964bfb1f0de6ab5ae1ff3a9..394cbc5c93e3600a8c918bfb673756bdd279ce7b 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 8300fb87b84ac1329d8facb1d560767c29c549d8..72cb0ddb9678d21eb2f2edd20a36b594b72160d9 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;