[ 3.5.yuz extended stable ] Patch "libceph: just set SOCK_CLOSED when state changes" 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: just set SOCK_CLOSED when state changes

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 e8d4410b595bb3c160244219711722dd95be9175 Mon Sep 17 00:00:00 2001
From: Alex Elder <elder at inktank.com>
Date: Wed, 20 Jun 2012 21:53:53 -0500
Subject: [PATCH 34/78] libceph: just set SOCK_CLOSED when state changes

commit d65c9e0b9eb43d14ece9dd843506ccba06162ee7 upstream.

When a TCP_CLOSE or TCP_CLOSE_WAIT event occurs, the SOCK_CLOSED
connection flag bit is set, and if it had not been previously set
queue_con() is called to ensure con_work() will get a chance to
handle the changed state.

con_work() atomically checks--and if set, clears--the SOCK_CLOSED
bit if it was set.  This means that even if the bit were set
repeatedly, the related processing in con_work() only gets called
once per transition of the bit from 0 to 1.

What's important then is that we ensure con_work() gets called *at
least* once when a socket close event occurs, not that it gets
called *exactly* once.

The work queue mechanism already takes care of queueing work
only if it is not already queued, so there's no need for us
to call queue_con() conditionally.

So this patch just makes it so the SOCK_CLOSED flag gets set
unconditionally in ceph_sock_state_change().

Signed-off-by: Alex Elder <elder at inktank.com>
Reviewed-by: Sage Weil <sage at inktank.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/ceph/messenger.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 5bd243e..cd1aaa8 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -261,8 +261,8 @@ static void ceph_sock_state_change(struct sock *sk)
 	case TCP_CLOSE_WAIT:
 		dout("%s TCP_CLOSE_WAIT\n", __func__);
 		con_sock_state_closing(con);
-		if (!test_and_set_bit(SOCK_CLOSED, &con->flags))
-			queue_con(con);
+		set_bit(SOCK_CLOSED, &con->flags);
+		queue_con(con);
 		break;
 	case TCP_ESTABLISHED:
 		dout("%s TCP_ESTABLISHED\n", __func__);
--
1.7.9.5