Patch "RDS: RDMA: return appropriate error on rdma map failures" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

RDS: RDMA: return appropriate error on rdma map failures

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
rds-rdma-return-appropriate-error-on-rdma-map-failures.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Santosh Shilimkar <[email protected]>
Date: Mon, 4 Jul 2016 17:04:37 -0700
Subject: RDS: RDMA: return appropriate error on rdma map failures

From: Santosh Shilimkar <[email protected]>

[ Upstream commit 584a8279a44a800dea5a5c1e9d53a002e03016b4 ]

The first message to a remote node should prompt a new connection even if it is RDMA operation. For RDMA operation the MR mapping can fail because connections is not yet up.

Since the connection establishment is asynchronous, we make sure the map failure because of unavailable connection reach to the user by appropriate error code. Before returning to the user, lets trigger the connection so that its ready for the next retry.

---
 net/rds/send.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

@@ -946,6 +946,11 @@ static int rds_cmsg_send(struct rds_sock
 			ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 			if (!ret)
 				*allocated_mr = 1;
+			else if (ret == -ENODEV)
+				/* Accommodate the get_mr() case which can fail
+				 * if connection isn't established yet.
+				 */
+				ret = -EAGAIN;
 			break;
 		case RDS_CMSG_ATOMIC_CSWP:
 		case RDS_CMSG_ATOMIC_FADD:

@@ -1114,8 +1119,12 @@ int rds_sendmsg(struct socket *sock, str
 
 	/* Parse any control messages the user may have included. */
 	ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
-	if (ret)
+	if (ret) {
+		/* Trigger connection so that its ready for the next retry */
+		if (ret ==  -EAGAIN)
+			rds_conn_connect_if_down(conn);
 		goto out;
+	}
 
 	if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
 		printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/rds-make-message-size-limit-compliant-with-spec.patch queue-4.9/rds-rdma-return-appropriate-error-on-rdma-map-failures.patch queue-4.9/rds-rdma-fix-the-ib_map_mr_sg_zbva-argument.patch