From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1327164094.1955.50.camel@aeonflux> Subject: Re: [PATCH] Bluetooth: Use non locking get_chan and explicit lock From: Marcel Holtmann To: Emeltchenko Andrei Cc: linux-bluetooth@vger.kernel.org Date: Sat, 21 Jan 2012 17:41:34 +0100 In-Reply-To: <1327060226-16211-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> References: <1327060226-16211-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Andrei, > For receiving ACL packets use __l2cap_get_chan_by_scid which is not > locking sk and explicitly lock sk after checking that it is exist. > Code looks nicer since now it is surrounded by lock/release. > > Signed-off-by: Andrei Emeltchenko > --- > net/bluetooth/l2cap_core.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c > index d16ad49..53dbfd3 100644 > --- a/net/bluetooth/l2cap_core.c > +++ b/net/bluetooth/l2cap_core.c > @@ -4243,7 +4243,7 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk > u16 tx_seq; > int len; > > - chan = l2cap_get_chan_by_scid(conn, cid); > + chan = __l2cap_get_chan_by_scid(conn, cid); > if (!chan) { > if (cid == L2CAP_CID_A2MP) { > chan = a2mp_channel_create(conn, skb); > @@ -4255,6 +4255,8 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk > } > > sk = chan->sk; > + if (sk) > + lock_sock(sk); this is the part I clearly do not like. This is pretty nasty conditional locking. We need to figure out something better. Regards Marcel