[PATCH 4.8 33/57] async_pq_val: fix DMA memory leak

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

From: Justin Maggard <jmaggard10@gmail.com>

commit c84750906b4818d4929fbf73a4ae6c113b94f52b upstream.

Add missing dmaengine_unmap_put(), so we don't OOM during RAID6 sync.

Fixes: 1786b943dad0 ("async_pq_val: convert to dmaengine_unmap_data")
Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 crypto/async_tx/async_pq.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -368,8 +368,6 @@ async_syndrome_val(struct page **blocks,
 
 		dma_set_unmap(tx, unmap);
 		async_tx_submit(chan, tx, submit);
-
-		return tx;
 	} else {
 		struct page *p_src = P(blocks, disks);
 		struct page *q_src = Q(blocks, disks);
@@ -424,9 +422,11 @@ async_syndrome_val(struct page **blocks,
 		submit->cb_param = cb_param_orig;
 		submit->flags = flags_orig;
 		async_tx_sync_epilog(submit);
-
-		return NULL;
+		tx = NULL;
 	}
+	dmaengine_unmap_put(unmap);
+
+	return tx;
 }
 EXPORT_SYMBOL_GPL(async_syndrome_val);