From: Patrick Caulfield <pcaulfie@redhat.com>
Subject: [RHEL5.1] bz#251179: [DLM] Reuse connections rather than freeing them
Date: Mon, 20 Aug 2007 16:03:14 +0100
Bugzilla: 251179
Message-Id: <46C9AD32.2020004@redhat.com>
Changelog: [DLM] Reuse connections rather than freeing them


This patch reuses 'othercon' connections rather than freeing them, thus avoiding
shutdown race conditions (bz#238490).

It also, and more importantly, fixes some close conditions missed by the
previous patch (clear othercon pointers) as well as being much tidier.

It is already upstream.

Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 631bc43..86c22bb 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -327,13 +327,12 @@ static void close_connection(struct connection *con, bool and_other)
 	if (con->othercon && and_other) {
 		/* Will only re-enter once. */
 		close_connection(con->othercon, 0);
-		kmem_cache_free(con_cache, con->othercon);
-		con->othercon = NULL;
 	}
 	if (con->rx_page) {
 		__free_page(con->rx_page);
 		con->rx_page = NULL;
 	}
+
 	con->retries = 0;
 	mutex_unlock(&con->sock_mutex);
 }
@@ -633,7 +632,7 @@ out_resched:
 
 out_close:
 	mutex_unlock(&con->sock_mutex);
-	if (ret != -EAGAIN && !test_bit(CF_IS_OTHERCON, &con->flags)) {
+	if (ret != -EAGAIN) {
 		close_connection(con, 0);
 		/* Reconnect when there is something to send */
 	}
@@ -722,6 +721,8 @@ static int tcp_accept_from_sock(struct connection *con)
 			INIT_WORK(&othercon->rwork, process_recv_sockets, othercon);
 			set_bit(CF_IS_OTHERCON, &othercon->flags);
 			newcon->othercon = othercon;
+		}
+		if (!othercon->sock) {
 			othercon->sock = newsock;
 			newsock->sk->sk_user_data = othercon;
 			add_sock(newsock, othercon);
@@ -1124,8 +1125,6 @@ static int tcp_listen_for_all(void)
 
 	log_print("Using TCP for communications");
 
-	set_bit(CF_IS_OTHERCON, &con->flags);
-
 	sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
 	if (sock) {
 		add_sock(sock, con);
@@ -1408,7 +1407,7 @@ void dlm_lowcomms_stop(void)
 	for (i = 0; i <= max_nodeid; i++) {
 		con = __nodeid2con(i, 0);
 		if (con) {
-			con->flags |= 0xFF;
+			con->flags |= 0x0F;
 			if (con->sock)
 				con->sock->sk->sk_user_data = NULL;
 		}