async_tx: use GFP_NOWAIT rather than GFP_IO

These async_XX functions are called from md/raid5 in an atomic
section, between get_cpu() and put_cpu(), so they must not sleep.
So use GFP_NOWAIT rather than GFP_IO.

Dan Williams writes: Longer term async_tx needs to be merged into md
directly as we can allocate this unmap data statically per-stripe
rather than per request.

Fixed: 7476bd79fc01 ("async_pq: convert to dmaengine_unmap_data")
Cc: stable@vger.kernel.org (v3.13+)
Reported-and-tested-by: Stanislav Samsonov <slava@annapurnalabs.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index e1bce26..da75777 100644
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -182,7 +182,7 @@
 	BUG_ON(src_cnt <= 1);
 
 	if (device)
-		unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOIO);
+		unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOWAIT);
 
 	if (unmap && is_dma_xor_aligned(device, offset, 0, len)) {
 		struct dma_async_tx_descriptor *tx;
@@ -278,7 +278,7 @@
 	BUG_ON(src_cnt <= 1);
 
 	if (device)
-		unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOIO);
+		unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOWAIT);
 
 	if (unmap && src_cnt <= device->max_xor &&
 	    is_dma_xor_aligned(device, offset, 0, len)) {