IB/iser: Use atomic allocations

Two minor flows in iSER's data path still use allocations; move them
to be atomic as a preperation step towards moving to use libiscsi
passthrough mode.

Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index 3be3a13..e27eb87 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -373,7 +373,7 @@
 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
 
-	tx_desc = kmem_cache_zalloc(ig.desc_cache, GFP_NOIO);
+	tx_desc = kmem_cache_zalloc(ig.desc_cache, GFP_ATOMIC);
 	if (tx_desc == NULL) {
 		iser_err("Failed to alloc desc for post dataout\n");
 		return -ENOMEM;