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Date: Wed, 15 Feb 2012 11:24:16 +0200
From: Emeltchenko Andrei <Andrei.Emeltchenko.news@gmail.com>
To: Ulisses Furquim <ulisses@profusion.mobi>,
	linux-bluetooth@vger.kernel.org
Subject: Re: [RFCv4 02/16] Bluetooth: Revert to mutexes from RCU list
Message-ID: <20120215092411.GC920@aemeltch-MOBL1>
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Hi Ulisses,

On Wed, Feb 15, 2012 at 10:16:53AM +0200, Emeltchenko Andrei wrote:
> On Tue, Feb 14, 2012 at 03:23:54PM -0200, Ulisses Furquim wrote:
> > On Tue, Feb 14, 2012 at 11:21 AM, Emeltchenko Andrei
> > <Andrei.Emeltchenko.news@gmail.com> wrote:
> > > Hi Ulisses,
> > >
> > > On Mon, Feb 13, 2012 at 10:06:10PM -0300, Ulisses Furquim wrote:
> > > ...
> > >> Yes, I do think they belong together. And please, check l2cap_sock.c
> > >> where l2cap_chan_close() seems to be called without locking
> > >> conn->chan_lock in l2cap_sock_shutdown().
> > >
> > > In that context we do not always have l2cap_conn so maybe we return
> > > chan list lock to chan_del or invent unlocked chan_del / chan_close?
> > 
> > We don't have l2cap_conn? So are we already on conn->chan_l list or
> > not? Maybe it's better to check that instead of changing everything
> > now.

Maybe this check?

 	if (!sk->sk_shutdown) {
+		struct l2cap_conn *conn = chan->conn;
+
 		if (chan->mode == L2CAP_MODE_ERTM)
 			err = __l2cap_wait_ack(sk);
 
 		sk->sk_shutdown = SHUTDOWN_MASK;
 		release_sock(sk);
+
+		if (conn)
+			mutex_lock(&conn->chan_lock);
 		l2cap_chan_close(chan, 0);
+		if (conn)
+			mutex_unlock(&conn->chan_lock);
+
 		lock_sock(sk);
 
 		if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
 			err = bt_sock_wait_state(sk, BT_CLOSED,
 							sk->sk_lingertime);

If it does not look too hackish...

Best regards 
Andrei Emeltchenko