[SCSI] iscsi_tcp: support PF_MEMALLOC/__GFP_MEMALLOC

This patch has software iscsi use PF_MEMALLOC/__GFP_MEMALLOC
to be able to better support swap over iscsi disks similar to
what was added for nbd.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 1b91ca0dc1e3..9e2588a6881c 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -370,17 +370,24 @@ static inline int iscsi_sw_tcp_xmit_qlen(struct iscsi_conn *conn)
 static int iscsi_sw_tcp_pdu_xmit(struct iscsi_task *task)
 {
         struct iscsi_conn *conn = task->conn;
-        int rc;
+        unsigned long pflags = current->flags;
+        int rc = 0;
+
+        current->flags |= PF_MEMALLOC;
 
         while (iscsi_sw_tcp_xmit_qlen(conn)) {
                 rc = iscsi_sw_tcp_xmit(conn);
-                if (rc == 0)
-                        return -EAGAIN;
+                if (rc == 0) {
+                        rc = -EAGAIN;
+                        break;
+                }
                 if (rc < 0)
-                        return rc;
+                        break;
+                rc = 0;
         }
 
-        return 0;
+        tsk_restore_flags(current, pflags, PF_MEMALLOC);
+        return rc;
 }
 
 /*
@@ -665,6 +672,7 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
         sk->sk_reuse = SK_CAN_REUSE;
         sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
         sk->sk_allocation = GFP_ATOMIC;
+        sk_set_memalloc(sk);
 
         iscsi_sw_tcp_conn_set_callbacks(conn);
         tcp_sw_conn->sendpage = tcp_sw_conn->sock->ops->sendpage;