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>
        struct dmaengine_unmap_data *unmap = NULL;
 
        if (device)
-               unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOIO);
+               unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
 
        if (unmap && is_dma_copy_aligned(device, src_offset, dest_offset, len)) {
                unsigned long dma_prep_flags = 0;
 
        BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
 
        if (device)
-               unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO);
+               unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
 
        /* XORing P/Q is only implemented in software */
        if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) &&
        BUG_ON(disks < 4);
 
        if (device)
-               unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO);
+               unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
 
        if (unmap && disks <= dma_maxpq(device, 0) &&
            is_dma_pq_aligned(device, offset, 0, len)) {
 
        u8 *a, *b, *c;
 
        if (dma)
-               unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOIO);
+               unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT);
 
        if (unmap) {
                struct device *dev = dma->dev;
        u8 *d, *s;
 
        if (dma)
-               unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOIO);
+               unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT);
 
        if (unmap) {
                dma_addr_t dma_dest[2];
 
        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;
        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)) {