Hi Andrei,
On Fri, Feb 10, 2012 at 11:54 AM, Emeltchenko Andrei
<Andrei.Emeltchenko.news@xxxxxxxxx> wrote:
> From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
>
> 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@xxxxxxxxx>
> ---
> net/bluetooth/l2cap_core.c | 98 ++++++++++++++++++++-----------------------
> 1 files changed, 46 insertions(+), 52 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 8dfccb3..ffc4179 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;
> }
>
> @@ -357,7 +343,9 @@ 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);
> }
>
> /* Delete channel.
> @@ -374,8 +362,7 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
>
> if (conn) {
> /* Delete from channel list */
> - list_del_rcu(&chan->list);
> - synchronize_rcu();
> + list_del(&chan->list);
>
> l2cap_chan_put(chan);
>
> @@ -426,10 +413,12 @@ static void l2cap_chan_cleanup_listen(struct sock *parent)
> /* Close not yet accepted channels */
> while ((sk = bt_accept_dequeue(parent, NULL))) {
> struct l2cap_chan *chan = l2cap_pi(sk)->chan;
> +
> __clear_chan_timer(chan);
> lock_sock(sk);
> l2cap_chan_close(chan, ECONNRESET);
> release_sock(sk);
> +
> chan->ops->close(chan->data);
> }
> }
> @@ -743,13 +732,13 @@ static void l2cap_send_disconn_req(struct l2cap_conn *conn, struct l2cap_chan *c
> /* ---- L2CAP connections ---- */
> static void l2cap_conn_start(struct l2cap_conn *conn)
> {
> - struct l2cap_chan *chan;
> + struct l2cap_chan *chan, *tmp;
>
> BT_DBG("conn %p", conn);
>
> - rcu_read_lock();
> + mutex_lock(&conn->chan_lock);
>
> - list_for_each_entry_rcu(chan, &conn->chan_l, list) {
> + list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {
> struct sock *sk = chan->sk;
>
> bh_lock_sock(sk);
> @@ -829,7 +818,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
> bh_unlock_sock(sk);
> }
>
> - rcu_read_unlock();
> + mutex_unlock(&conn->chan_lock);
> }
>
> /* Find socket with cid and source bdaddr.
> @@ -941,9 +930,9 @@ static void l2cap_conn_ready(struct l2cap_conn *conn)
> if (conn->hcon->out && conn->hcon->type == LE_LINK)
> smp_conn_security(conn, conn->hcon->pending_sec_level);
>
> - rcu_read_lock();
> + mutex_lock(&conn->chan_lock);
>
> - list_for_each_entry_rcu(chan, &conn->chan_l, list) {
> + list_for_each_entry(chan, &conn->chan_l, list) {
> struct sock *sk = chan->sk;
>
> bh_lock_sock(sk);
> @@ -963,7 +952,7 @@ static void l2cap_conn_ready(struct l2cap_conn *conn)
> bh_unlock_sock(sk);
> }
>
> - rcu_read_unlock();
> + mutex_unlock(&conn->chan_lock);
> }
>
> /* Notify sockets that we cannot guaranty reliability anymore */
> @@ -973,16 +962,16 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
>
> BT_DBG("conn %p", conn);
>
> - rcu_read_lock();
> + mutex_lock(&conn->chan_lock);
>
> - list_for_each_entry_rcu(chan, &conn->chan_l, list) {
> + list_for_each_entry(chan, &conn->chan_l, list) {
> struct sock *sk = chan->sk;
>
> if (test_bit(FLAG_FORCE_RELIABLE, &chan->flags))
> sk->sk_err = err;
> }
>
> - rcu_read_unlock();
> + mutex_unlock(&conn->chan_lock);
> }
>
> static void l2cap_info_timeout(struct work_struct *work)
> @@ -1009,6 +998,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
>
> kfree_skb(conn->rx_skb);
>
> + mutex_lock(&conn->chan_lock);
> +
> /* Kill channels */
> list_for_each_entry_safe(chan, l, &conn->chan_l, list) {
> sk = chan->sk;
> @@ -1018,6 +1009,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
> chan->ops->close(chan->data);
> }
>
> + mutex_unlock(&conn->chan_lock);
> +
> hci_chan_del(conn->hchan);
>
> if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT)
> @@ -1075,6 +1068,7 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
> conn->feat_mask = 0;
>
> spin_lock_init(&conn->lock);
> + mutex_init(&conn->chan_lock);
>
> INIT_LIST_HEAD(&conn->chan_l);
>
> @@ -1815,9 +1809,9 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
>
> BT_DBG("conn %p", conn);
>
> - rcu_read_lock();
> + mutex_lock(&conn->chan_lock);
>
> - list_for_each_entry_rcu(chan, &conn->chan_l, list) {
> + list_for_each_entry(chan, &conn->chan_l, list) {
> struct sock *sk = chan->sk;
> if (chan->chan_type != L2CAP_CHAN_RAW)
> continue;
> @@ -1833,7 +1827,7 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
> kfree_skb(nskb);
> }
>
> - rcu_read_unlock();
> + mutex_unlock(&conn->chan_lock);
> }
>
> /* ---- L2CAP signalling commands ---- */
> @@ -4515,9 +4509,9 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
> cancel_delayed_work(&conn->security_timer);
> }
>
> - rcu_read_lock();
> + mutex_lock(&conn->chan_lock);
>
> - list_for_each_entry_rcu(chan, &conn->chan_l, list) {
> + list_for_each_entry(chan, &conn->chan_l, list) {
> struct sock *sk = chan->sk;
>
> bh_lock_sock(sk);
> @@ -4597,7 +4591,7 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
> bh_unlock_sock(sk);
> }
>
> - rcu_read_unlock();
> + mutex_unlock(&conn->chan_lock);
>
> return 0;
> }
> --
> 1.7.8.3
No need to lock and unlock conn->chan_lock in l2cap_disconnect_rsp()?
This change from RCU to mutexes really should be just one commit IMO.
This series is starting to get all confused. The change to RCU was
only one commit so it should be possible to do the "revert" without
breaking anything.
Regards,
--
Ulisses Furquim
ProFUSION embedded systems
http://profusion.mobi
Mobile: +55 19 9250 0942
Skype: ulissesffs
--
To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
