From: Gustavo Padovan <padovan@profusion.mobi>
To: Emeltchenko Andrei <Andrei.Emeltchenko.news@gmail.com>
Cc: linux-bluetooth@vger.kernel.org
Subject: Re: [RFCv3 02/16] Bluetooth: Revert to mutexes from RCU list
Date: Thu, 9 Feb 2012 16:37:59 -0200 [thread overview]
Message-ID: <20120209183759.GC3174@joana> (raw)
In-Reply-To: <1328797057-26331-3-git-send-email-Andrei.Emeltchenko.news@gmail.com>
Hi Andrei,
* Emeltchenko Andrei <Andrei.Emeltchenko.news@gmail.com> [2012-02-09 16:17:23 +0200]:
> From: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
>
> Usage of RCU list looks not reasonalbe for a number of reasons:
> our code sleep and we have to use socket spinlocks, some parts
> of code are updaters thus we need to use mutexes anyway.
>
> Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
> ---
> net/bluetooth/l2cap_core.c | 108 ++++++++++++++++++++++----------------------
> 1 files changed, 54 insertions(+), 54 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 8dfccb3..ae08944 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -77,36 +77,24 @@ static void l2cap_send_disconn_req(struct l2cap_conn *conn,
>
> static struct l2cap_chan *__l2cap_get_chan_by_dcid(struct l2cap_conn *conn, u16 cid)
> {
> - struct l2cap_chan *c, *r = NULL;
> -
> - rcu_read_lock();
> + struct l2cap_chan *c;
>
> - list_for_each_entry_rcu(c, &conn->chan_l, list) {
> - if (c->dcid == cid) {
> - r = c;
> - break;
> - }
> + list_for_each_entry(c, &conn->chan_l, list) {
> + if (c->dcid == cid)
> + return c;
> }
> -
> - rcu_read_unlock();
> - return r;
> + return NULL;
> }
>
> static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid)
> {
> - struct l2cap_chan *c, *r = NULL;
> -
> - rcu_read_lock();
> + struct l2cap_chan *c;
>
> - list_for_each_entry_rcu(c, &conn->chan_l, list) {
> - if (c->scid == cid) {
> - r = c;
> - break;
> - }
> + list_for_each_entry(c, &conn->chan_l, list) {
> + if (c->scid == cid)
> + return c;
> }
> -
> - rcu_read_unlock();
> - return r;
> + return NULL;
> }
>
> /* Find channel with given SCID.
> @@ -115,36 +103,34 @@ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 ci
> {
> struct l2cap_chan *c;
>
> + mutex_lock(&conn->chan_lock);
> c = __l2cap_get_chan_by_scid(conn, cid);
> if (c)
> lock_sock(c->sk);
> + mutex_unlock(&conn->chan_lock);
> return c;
> }
>
> static struct l2cap_chan *__l2cap_get_chan_by_ident(struct l2cap_conn *conn, u8 ident)
> {
> - struct l2cap_chan *c, *r = NULL;
> -
> - rcu_read_lock();
> + struct l2cap_chan *c;
>
> - list_for_each_entry_rcu(c, &conn->chan_l, list) {
> - if (c->ident == ident) {
> - r = c;
> - break;
> - }
> + list_for_each_entry(c, &conn->chan_l, list) {
> + if (c->ident == ident)
> + return c;
> }
> -
> - rcu_read_unlock();
> - return r;
> + return NULL;
> }
>
> static inline struct l2cap_chan *l2cap_get_chan_by_ident(struct l2cap_conn *conn, u8 ident)
> {
> struct l2cap_chan *c;
>
> + mutex_lock(&conn->chan_lock);
> c = __l2cap_get_chan_by_ident(conn, ident);
> if (c)
> lock_sock(c->sk);
> + mutex_unlock(&conn->chan_lock);
> return c;
> }
>
> @@ -259,6 +245,7 @@ static void l2cap_chan_timeout(struct work_struct *work)
>
> BT_DBG("chan %p state %d", chan, chan->state);
>
> + mutex_lock(&chan->conn->chan_lock);
> lock_sock(sk);
>
> if (chan->state == BT_CONNECTED || chan->state == BT_CONFIG)
> @@ -272,6 +259,7 @@ static void l2cap_chan_timeout(struct work_struct *work)
> l2cap_chan_close(chan, reason);
>
> release_sock(sk);
> + mutex_unlock(&chan->conn->chan_lock);
>
> chan->ops->close(chan->data);
> l2cap_chan_put(chan);
> @@ -357,7 +345,9 @@ static void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
>
> l2cap_chan_hold(chan);
>
> - list_add_rcu(&chan->list, &conn->chan_l);
> + mutex_lock(&conn->chan_lock);
> + list_add(&chan->list, &conn->chan_l);
> + mutex_unlock(&conn->chan_lock);
Check the commit that added RCU to our list, I think you are missing to revert
some parts of it.
Gustavo
next prev parent reply other threads:[~2012-02-09 18:37 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-09 14:17 [RFCv3 00/16] Bluetooth: Change socket lock to l2cap_chan lock Emeltchenko Andrei
2012-02-09 14:17 ` [RFCv3 01/16] Bluetooth: trivial: Fix long line Emeltchenko Andrei
2012-02-09 14:26 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 02/16] Bluetooth: Revert to mutexes from RCU list Emeltchenko Andrei
2012-02-09 14:27 ` Marcel Holtmann
2012-02-09 17:54 ` Ulisses Furquim
2012-02-10 8:09 ` Emeltchenko Andrei
2012-02-09 18:37 ` Gustavo Padovan [this message]
2012-02-09 18:48 ` Ulisses Furquim
2012-02-09 14:17 ` [RFCv3 03/16] Bluetooth: Do not use sk lock in get_chan functions Emeltchenko Andrei
2012-02-09 14:28 ` Marcel Holtmann
2012-02-09 14:40 ` Emeltchenko Andrei
2012-02-09 18:08 ` Gustavo Padovan
2012-02-09 18:33 ` Ulisses Furquim
2012-02-10 8:16 ` Emeltchenko Andrei
2012-02-09 14:17 ` [RFCv3 04/16] Bluetooth: Add l2cap_chan_lock Emeltchenko Andrei
2012-02-09 19:24 ` Gustavo Padovan
2012-02-10 8:39 ` Emeltchenko Andrei
2012-02-09 14:17 ` [RFCv3 05/16] Bluetooth: Add locked and unlocked state_change Emeltchenko Andrei
2012-02-09 14:17 ` [RFCv3 06/16] Bluetooth: Add socket error function Emeltchenko Andrei
2012-02-09 14:30 ` Marcel Holtmann
2012-02-09 18:13 ` Gustavo Padovan
2012-02-10 8:46 ` Emeltchenko Andrei
2012-02-10 12:40 ` Gustavo Padovan
2012-02-09 14:17 ` [RFCv3 07/16] Bluetooth: Add unlocked __l2cap_chan_add function Emeltchenko Andrei
2012-02-09 14:31 ` Marcel Holtmann
2012-02-09 17:54 ` Ulisses Furquim
2012-02-10 8:53 ` Emeltchenko Andrei
2012-02-09 14:17 ` [RFCv3 08/16] Bluetooth: Use chan lock in timers Emeltchenko Andrei
2012-02-09 14:33 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 09/16] Bluetooth: Use chan lock in L2CAP sig commands Emeltchenko Andrei
2012-02-09 14:35 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 10/16] Bluetooth: Use chan lock in chan delete functions Emeltchenko Andrei
2012-02-09 14:36 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 11/16] Bluetooth: Use chan lock in L2CAP conn start Emeltchenko Andrei
2012-02-09 14:37 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 12/16] Bluetooth: Use chan lock in receiving data Emeltchenko Andrei
2012-02-09 14:38 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 13/16] Bluetooth: Change locking logic for conn/chan ready Emeltchenko Andrei
2012-02-09 14:39 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 14/16] Bluetooth: Change locking logic in security_cfm Emeltchenko Andrei
2012-02-09 14:40 ` Marcel Holtmann
2012-02-09 14:17 ` [RFCv3 15/16] Bluetooth: Use l2cap chan lock in socket connect Emeltchenko Andrei
2012-02-09 14:42 ` Marcel Holtmann
2012-02-09 18:25 ` Ulisses Furquim
2012-02-10 9:18 ` Emeltchenko Andrei
2012-02-10 18:31 ` Ulisses Furquim
2012-02-13 8:47 ` Emeltchenko Andrei
2012-02-14 1:12 ` Ulisses Furquim
2012-02-09 14:17 ` [RFCv3 16/16] Bluetooth: Remove socket lock check Emeltchenko Andrei
2012-02-09 14:43 ` Marcel Holtmann
2012-02-09 14:50 ` Emeltchenko Andrei
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