From: Ka-Cheong Poon <ka-cheong.poon@oracle.com>
Date: Tue, 2 Oct 2018 14:50:02 +0000 (-0700)
Subject: rds: RDS (tcp) hangs on sendto() to unresponding address
X-Git-Tag: v4.1.12-124.31.3~488
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4d8376fac652927fcc94ca88db134ce7822c03c1;p=users%2Fjedix%2Flinux-maple.git

rds: RDS (tcp) hangs on sendto() to unresponding address

In rds_send_mprds_hash(), if the calculated hash value is non-zero and
the MPRDS connections are not yet up, it will wait.  But it should not
wait if the send is non-blocking.  In this case, it should just use the
base c_path for sending the message.

Orabug: 28762608

Signed-off-by: Ka-Cheong Poon <ka-cheong.poon@oracle.com>
Reviewed-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>
---

diff --git a/net/rds/send.c b/net/rds/send.c
index 6a753aeafe913..c1ca5a12e512f 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -1182,7 +1182,8 @@ static inline int rds_rdma_bytes(struct msghdr *msg, size_t *rdma_bytes)
 	return 0;
 }
 
-static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
+static int rds_send_mprds_hash(struct rds_sock *rs,
+			       struct rds_connection *conn, int nonblock)
 {
 	int hash;
 
@@ -1194,6 +1195,11 @@ static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
 		rds_send_ping(conn, 0);
 
 		if (conn->c_npaths == 0) {
+			/* Cannot wait for the connection be made, so just use
+			 * the base c_path.
+			 */
+			if (nonblock)
+				return 0;
 			wait_event_interruptible(conn->c_hs_waitq,
 						 (conn->c_npaths != 0));
 		}
@@ -1386,7 +1392,7 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 	}
 
 	if (conn->c_trans->t_mp_capable)
-		cpath = &conn->c_path[rds_send_mprds_hash(rs, conn)];
+		cpath = &conn->c_path[rds_send_mprds_hash(rs, conn, nonblock)];
 	else
 		cpath = &conn->c_path[0];