netdev - [PATCH net 1/2] RDS: TCP: rds_tcp_accept_worker() must exit gracefully when terminating rds-tcp

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Date:	Wed, 18 May 2016 10:06:23 -0700
From:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, rds-devel@....oracle.com,
	ajaykumar.hotchandani@...cle.com, sowmini.varadhan@...cle.com,
	santosh.shilimkar@...cle.com
Subject: [PATCH net 1/2] RDS: TCP: rds_tcp_accept_worker() must exit gracefully when terminating rds-tcp

There are two instances where we want to terminate RDS-TCP: when
exiting the netns or during module unload. In either case, the
termination sequence is to stop the listen socket, mark the
rtn->rds_tcp_listen_sock as null, and flush any accept workqs.
Thus any workqs that get flushed at this point will encounter a
null rds_tcp_listen_sock, and must exit gracefully to allow
the RDS-TCP termination to complete successfully.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@...cle.com>
---
 net/rds/tcp_listen.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index be263cd..e10b422 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -80,6 +80,9 @@ int rds_tcp_accept_one(struct socket *sock)
 	int conn_state;
 	struct sock *nsk;
 
+	if (!sock) /* module unload or netns delete in progress */
+		return -ENETUNREACH;
+
 	ret = sock_create_kern(sock_net(sock->sk), sock->sk->sk_family,
 			       sock->sk->sk_type, sock->sk->sk_protocol,
 			       &new_sock);
-- 
1.7.1