[ 3.5.yuz extended stable ] Patch "libceph: move msgr clear_standby under con mutex" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    libceph: move msgr clear_standby under con mutex

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.yuz tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From cf37445bf770308faad84523540c53086e0bdcbe Mon Sep 17 00:00:00 2001
From: Sage Weil <sage at inktank.com>
Date: Fri, 20 Jul 2012 15:33:04 -0700
Subject: [PATCH 55/78] libceph: move msgr clear_standby under con mutex
 protection

commit 00650931e52e97fe64096bec167f5a6780dfd94a upstream.

Avoid dropping and retaking con->mutex in the ceph_con_send() case by
leaving locking up to the caller.

Signed-off-by: Sage Weil <sage at inktank.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/ceph/messenger.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 9aaf539..1a3cb4a 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2441,12 +2441,10 @@ static void clear_standby(struct ceph_connection *con)
 {
 	/* come back from STANDBY? */
 	if (test_and_clear_bit(STANDBY, &con->state)) {
-		mutex_lock(&con->mutex);
 		dout("clear_standby %p and ++connect_seq\n", con);
 		con->connect_seq++;
 		WARN_ON(test_bit(WRITE_PENDING, &con->flags));
 		WARN_ON(test_bit(KEEPALIVE_PENDING, &con->flags));
-		mutex_unlock(&con->mutex);
 	}
 }

@@ -2483,11 +2481,12 @@ void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg)
 	     le32_to_cpu(msg->hdr.front_len),
 	     le32_to_cpu(msg->hdr.middle_len),
 	     le32_to_cpu(msg->hdr.data_len));
+
+	clear_standby(con);
 	mutex_unlock(&con->mutex);

 	/* if there wasn't anything waiting to send before, queue
 	 * new work */
-	clear_standby(con);
 	if (test_and_set_bit(WRITE_PENDING, &con->flags) == 0)
 		queue_con(con);
 }
@@ -2574,7 +2573,9 @@ void ceph_msg_revoke_incoming(struct ceph_msg *msg)
 void ceph_con_keepalive(struct ceph_connection *con)
 {
 	dout("con_keepalive %p\n", con);
+	mutex_lock(&con->mutex);
 	clear_standby(con);
+	mutex_unlock(&con->mutex);
 	if (test_and_set_bit(KEEPALIVE_PENDING, &con->flags) == 0 &&
 	    test_and_set_bit(WRITE_PENDING, &con->flags) == 0)
 		queue_con(con);
--
1.7.9.5