Bluetooth: Change l2cap chan_list to use RCU
This list has much more reads than writes, so RCU makes senses here, also it avoid deadlock against the socket lock. Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This commit is contained in:
Gustavo F. Padovan
parent
03a0019481
commit
3d57dc6806
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@ -89,24 +89,36 @@ static inline void chan_put(struct l2cap_chan *c)
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static struct l2cap_chan *__l2cap_get_chan_by_dcid(struct l2cap_conn *conn, u16 cid)
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{
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struct l2cap_chan *c;
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struct l2cap_chan *c, *r = NULL;
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list_for_each_entry(c, &conn->chan_l, list) {
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if (c->dcid == cid)
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return c;
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rcu_read_lock();
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list_for_each_entry_rcu(c, &conn->chan_l, list) {
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if (c->dcid == cid) {
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r = c;
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break;
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}
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}
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return NULL;
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rcu_read_unlock();
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return r;
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}
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static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid)
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{
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struct l2cap_chan *c;
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struct l2cap_chan *c, *r = NULL;
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list_for_each_entry(c, &conn->chan_l, list) {
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if (c->scid == cid)
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return c;
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rcu_read_lock();
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list_for_each_entry_rcu(c, &conn->chan_l, list) {
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if (c->scid == cid) {
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r = c;
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break;
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}
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}
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return NULL;
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rcu_read_unlock();
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return r;
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}
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/* Find channel with given SCID.
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@ -115,34 +127,36 @@ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 ci
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{
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struct l2cap_chan *c;
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mutex_lock(&conn->chan_lock);
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c = __l2cap_get_chan_by_scid(conn, cid);
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if (c)
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lock_sock(c->sk);
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mutex_unlock(&conn->chan_lock);
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return c;
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}
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static struct l2cap_chan *__l2cap_get_chan_by_ident(struct l2cap_conn *conn, u8 ident)
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{
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struct l2cap_chan *c;
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struct l2cap_chan *c, *r = NULL;
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list_for_each_entry(c, &conn->chan_l, list) {
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if (c->ident == ident)
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return c;
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rcu_read_lock();
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list_for_each_entry_rcu(c, &conn->chan_l, list) {
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if (c->ident == ident) {
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r = c;
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break;
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}
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}
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return NULL;
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rcu_read_unlock();
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return r;
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}
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static inline struct l2cap_chan *l2cap_get_chan_by_ident(struct l2cap_conn *conn, u8 ident)
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{
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struct l2cap_chan *c;
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mutex_lock(&conn->chan_lock);
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c = __l2cap_get_chan_by_ident(conn, ident);
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if (c)
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lock_sock(c->sk);
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mutex_unlock(&conn->chan_lock);
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return c;
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}
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@ -323,7 +337,7 @@ void l2cap_chan_destroy(struct l2cap_chan *chan)
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chan_put(chan);
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}
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static void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
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static void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
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{
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BT_DBG("conn %p, psm 0x%2.2x, dcid 0x%4.4x", conn,
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chan->psm, chan->dcid);
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@ -364,7 +378,7 @@ static void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
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chan_hold(chan);
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list_add(&chan->list, &conn->chan_l);
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list_add_rcu(&chan->list, &conn->chan_l);
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}
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/* Delete channel.
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@ -381,9 +395,9 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
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if (conn) {
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/* Delete from channel list */
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mutex_lock(&conn->chan_lock);
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list_del(&chan->list);
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mutex_unlock(&conn->chan_lock);
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list_del_rcu(&chan->list);
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synchronize_rcu();
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chan_put(chan);
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chan->conn = NULL;
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@ -750,13 +764,13 @@ static void l2cap_send_disconn_req(struct l2cap_conn *conn, struct l2cap_chan *c
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/* ---- L2CAP connections ---- */
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static void l2cap_conn_start(struct l2cap_conn *conn)
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{
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struct l2cap_chan *chan, *tmp;
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struct l2cap_chan *chan;
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BT_DBG("conn %p", conn);
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mutex_lock(&conn->chan_lock);
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rcu_read_lock();
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list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {
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list_for_each_entry_rcu(chan, &conn->chan_l, list) {
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struct sock *sk = chan->sk;
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bh_lock_sock(sk);
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@ -780,9 +794,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
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&chan->conf_state)) {
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/* l2cap_chan_close() calls list_del(chan)
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* so release the lock */
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mutex_unlock(&conn->chan_lock);
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l2cap_chan_close(chan, ECONNRESET);
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utex_lock(&conn->chan_lock);
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bh_unlock_sock(sk);
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continue;
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}
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@ -838,7 +850,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
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bh_unlock_sock(sk);
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}
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mutex_unlock(&conn->chan_lock);
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rcu_read_unlock();
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}
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/* Find socket with cid and source bdaddr.
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@ -903,8 +915,6 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn)
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sk = chan->sk;
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mutex_lock(&conn->chan_lock);
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hci_conn_hold(conn->hcon);
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bacpy(&bt_sk(sk)->src, conn->src);
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@ -912,15 +922,13 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn)
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bt_accept_enqueue(parent, sk);
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__l2cap_chan_add(conn, chan);
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l2cap_chan_add(conn, chan);
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__set_chan_timer(chan, sk->sk_sndtimeo);
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l2cap_state_change(chan, BT_CONNECTED);
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parent->sk_data_ready(parent, 0);
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mutex_unlock(&conn->chan_lock);
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clean:
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release_sock(parent);
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}
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@ -954,9 +962,9 @@ static void l2cap_conn_ready(struct l2cap_conn *conn)
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if (conn->hcon->out && conn->hcon->type == LE_LINK)
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smp_conn_security(conn, conn->hcon->pending_sec_level);
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mutex_lock(&conn->chan_lock);
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rcu_read_lock();
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list_for_each_entry(chan, &conn->chan_l, list) {
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list_for_each_entry_rcu(chan, &conn->chan_l, list) {
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struct sock *sk = chan->sk;
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bh_lock_sock(sk);
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@ -976,7 +984,7 @@ static void l2cap_conn_ready(struct l2cap_conn *conn)
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bh_unlock_sock(sk);
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}
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mutex_unlock(&conn->chan_lock);
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rcu_read_unlock();
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}
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/* Notify sockets that we cannot guaranty reliability anymore */
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@ -986,16 +994,16 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
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BT_DBG("conn %p", conn);
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mutex_lock(&conn->chan_lock);
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rcu_read_lock();
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list_for_each_entry(chan, &conn->chan_l, list) {
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list_for_each_entry_rcu(chan, &conn->chan_l, list) {
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struct sock *sk = chan->sk;
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if (test_bit(FLAG_FORCE_RELIABLE, &chan->flags))
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sk->sk_err = err;
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}
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mutex_unlock(&conn->chan_lock);
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rcu_read_unlock();
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}
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static void l2cap_info_timeout(struct work_struct *work)
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@ -1087,7 +1095,6 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
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conn->feat_mask = 0;
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spin_lock_init(&conn->lock);
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mutex_init(&conn->chan_lock);
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INIT_LIST_HEAD(&conn->chan_l);
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@ -1102,13 +1109,6 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
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return conn;
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}
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static inline void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
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{
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mutex_lock(&conn->chan_lock);
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__l2cap_chan_add(conn, chan);
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mutex_unlock(&conn->chan_lock);
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}
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/* ---- Socket interface ---- */
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/* Find socket with psm and source bdaddr.
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@ -1825,8 +1825,9 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
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BT_DBG("conn %p", conn);
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mutex_lock(&conn->chan_lock);
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list_for_each_entry(chan, &conn->chan_l, list) {
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rcu_read_lock();
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list_for_each_entry_rcu(chan, &conn->chan_l, list) {
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struct sock *sk = chan->sk;
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if (chan->chan_type != L2CAP_CHAN_RAW)
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continue;
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@ -1841,7 +1842,8 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
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if (chan->ops->recv(chan->data, nskb))
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kfree_skb(nskb);
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}
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mutex_unlock(&conn->chan_lock);
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rcu_read_unlock();
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}
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/* ---- L2CAP signalling commands ---- */
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@ -2641,11 +2643,8 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
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sk = chan->sk;
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mutex_lock(&conn->chan_lock);
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/* Check if we already have channel with that dcid */
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if (__l2cap_get_chan_by_dcid(conn, scid)) {
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mutex_unlock(&conn->chan_lock);
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sock_set_flag(sk, SOCK_ZAPPED);
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chan->ops->close(chan->data);
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goto response;
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@ -2660,7 +2659,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
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bt_accept_enqueue(parent, sk);
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__l2cap_chan_add(conn, chan);
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l2cap_chan_add(conn, chan);
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dcid = chan->scid;
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@ -2691,8 +2690,6 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
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status = L2CAP_CS_NO_INFO;
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}
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mutex_unlock(&conn->chan_lock);
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response:
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release_sock(parent);
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@ -4528,9 +4525,9 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
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del_timer(&conn->security_timer);
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}
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mutex_lock(&conn->chan_lock);
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rcu_read_lock();
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list_for_each_entry(chan, &conn->chan_l, list) {
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list_for_each_entry_rcu(chan, &conn->chan_l, list) {
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struct sock *sk = chan->sk;
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bh_lock_sock(sk);
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@ -4608,7 +4605,7 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
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bh_unlock_sock(sk);
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}
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mutex_unlock(&conn->chan_lock);
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rcu_read_unlock();
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return 0;
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}
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