Commit 3d57dc68 authored by Gustavo Padovan's avatar Gustavo Padovan
Browse files

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: default avatarMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: default avatarGustavo F. Padovan <padovan@profusion.mobi>
parent 03a00194

net/bluetooth/l2cap_core.c

+58 −61
Original line number Diff line number Diff line
@@ -89,24 +89,36 @@ static inline void chan_put(struct l2cap_chan *c) 


static struct l2cap_chan *__l2cap_get_chan_by_dcid(struct l2cap_conn *conn, u16 cid)

{

	struct l2cap_chan *c;

	struct l2cap_chan *c, *r = NULL;



	list_for_each_entry(c, &conn->chan_l, list) {

		if (c->dcid == cid)

			return c;

	rcu_read_lock();



	list_for_each_entry_rcu(c, &conn->chan_l, list) {

		if (c->dcid == cid) {

			r = c;

			break;

		}

	return NULL;

	}



	rcu_read_unlock();

	return r;

}



static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid)

{

	struct l2cap_chan *c;

	struct l2cap_chan *c, *r = NULL;



	list_for_each_entry(c, &conn->chan_l, list) {

		if (c->scid == cid)

			return c;

	rcu_read_lock();



	list_for_each_entry_rcu(c, &conn->chan_l, list) {

		if (c->scid == cid) {

			r = c;

			break;

		}

	return NULL;

	}



	rcu_read_unlock();

	return r;

}



/* Find channel with given SCID.
@@ -115,34 +127,36 @@ 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;

	struct l2cap_chan *c, *r = NULL;



	list_for_each_entry(c, &conn->chan_l, list) {

		if (c->ident == ident)

			return c;

	rcu_read_lock();



	list_for_each_entry_rcu(c, &conn->chan_l, list) {

		if (c->ident == ident) {

			r = c;

			break;

		}

	return NULL;

	}



	rcu_read_unlock();

	return r;

}



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;

}
@@ -323,7 +337,7 @@ void l2cap_chan_destroy(struct l2cap_chan *chan) 
	chan_put(chan);

}



static void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)

static void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)

{

	BT_DBG("conn %p, psm 0x%2.2x, dcid 0x%4.4x", conn,

			chan->psm, chan->dcid);
@@ -364,7 +378,7 @@ static void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan) 


	chan_hold(chan);



	list_add(&chan->list, &conn->chan_l);

	list_add_rcu(&chan->list, &conn->chan_l);

}



/* Delete channel.
@@ -381,9 +395,9 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err) 


	if (conn) {

		/* Delete from channel list */

		mutex_lock(&conn->chan_lock);

		list_del(&chan->list);

		mutex_unlock(&conn->chan_lock);

		list_del_rcu(&chan->list);

		synchronize_rcu();



		chan_put(chan);



		chan->conn = NULL;
@@ -750,13 +764,13 @@ 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, *tmp;

	struct l2cap_chan *chan;



	BT_DBG("conn %p", conn);



	mutex_lock(&conn->chan_lock);

	rcu_read_lock();



	list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {

	list_for_each_entry_rcu(chan, &conn->chan_l, list) {

		struct sock *sk = chan->sk;



		bh_lock_sock(sk);
@@ -780,9 +794,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn) 
					&chan->conf_state)) {

				/* l2cap_chan_close() calls list_del(chan)

				 * so release the lock */

				mutex_unlock(&conn->chan_lock);

				l2cap_chan_close(chan, ECONNRESET);

				utex_lock(&conn->chan_lock);

				bh_unlock_sock(sk);

				continue;

			}
@@ -838,7 +850,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn) 
		bh_unlock_sock(sk);

	}



	mutex_unlock(&conn->chan_lock);

	rcu_read_unlock();

}



/* Find socket with cid and source bdaddr.
@@ -903,8 +915,6 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn) 


	sk = chan->sk;



	mutex_lock(&conn->chan_lock);



	hci_conn_hold(conn->hcon);



	bacpy(&bt_sk(sk)->src, conn->src);
@@ -912,15 +922,13 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn) 


	bt_accept_enqueue(parent, sk);



	__l2cap_chan_add(conn, chan);

	l2cap_chan_add(conn, chan);



	__set_chan_timer(chan, sk->sk_sndtimeo);



	l2cap_state_change(chan, BT_CONNECTED);

	parent->sk_data_ready(parent, 0);



	mutex_unlock(&conn->chan_lock);



clean:

	release_sock(parent);

}
@@ -954,9 +962,9 @@ 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);



	mutex_lock(&conn->chan_lock);

	rcu_read_lock();



	list_for_each_entry(chan, &conn->chan_l, list) {

	list_for_each_entry_rcu(chan, &conn->chan_l, list) {

		struct sock *sk = chan->sk;



		bh_lock_sock(sk);
@@ -976,7 +984,7 @@ static void l2cap_conn_ready(struct l2cap_conn *conn) 
		bh_unlock_sock(sk);

	}



	mutex_unlock(&conn->chan_lock);

	rcu_read_unlock();

}



/* Notify sockets that we cannot guaranty reliability anymore */
@@ -986,16 +994,16 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err) 


	BT_DBG("conn %p", conn);



	mutex_lock(&conn->chan_lock);

	rcu_read_lock();



	list_for_each_entry(chan, &conn->chan_l, list) {

	list_for_each_entry_rcu(chan, &conn->chan_l, list) {

		struct sock *sk = chan->sk;



		if (test_bit(FLAG_FORCE_RELIABLE, &chan->flags))

			sk->sk_err = err;

	}



	mutex_unlock(&conn->chan_lock);

	rcu_read_unlock();

}



static void l2cap_info_timeout(struct work_struct *work)
@@ -1087,7 +1095,6 @@ 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);
@@ -1102,13 +1109,6 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status) 
	return conn;

}



static inline void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)

{

	mutex_lock(&conn->chan_lock);

	__l2cap_chan_add(conn, chan);

	mutex_unlock(&conn->chan_lock);

}



/* ---- Socket interface ---- */



/* Find socket with psm and source bdaddr.
@@ -1825,8 +1825,9 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb) 


	BT_DBG("conn %p", conn);



	mutex_lock(&conn->chan_lock);

	list_for_each_entry(chan, &conn->chan_l, list) {

	rcu_read_lock();



	list_for_each_entry_rcu(chan, &conn->chan_l, list) {

		struct sock *sk = chan->sk;

		if (chan->chan_type != L2CAP_CHAN_RAW)

			continue;
@@ -1841,7 +1842,8 @@ static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb) 
		if (chan->ops->recv(chan->data, nskb))

			kfree_skb(nskb);

	}

	mutex_unlock(&conn->chan_lock);



	rcu_read_unlock();

}



/* ---- L2CAP signalling commands ---- */
@@ -2641,11 +2643,8 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd 


	sk = chan->sk;



	mutex_lock(&conn->chan_lock);



	/* Check if we already have channel with that dcid */

	if (__l2cap_get_chan_by_dcid(conn, scid)) {

		mutex_unlock(&conn->chan_lock);

		sock_set_flag(sk, SOCK_ZAPPED);

		chan->ops->close(chan->data);

		goto response;
@@ -2660,7 +2659,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd 


	bt_accept_enqueue(parent, sk);



	__l2cap_chan_add(conn, chan);

	l2cap_chan_add(conn, chan);



	dcid = chan->scid;
@@ -2691,8 +2690,6 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd 
		status = L2CAP_CS_NO_INFO;

	}



	mutex_unlock(&conn->chan_lock);



response:

	release_sock(parent);
@@ -4528,9 +4525,9 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt) 
		del_timer(&conn->security_timer);

	}



	mutex_lock(&conn->chan_lock);

	rcu_read_lock();



	list_for_each_entry(chan, &conn->chan_l, list) {

	list_for_each_entry_rcu(chan, &conn->chan_l, list) {

		struct sock *sk = chan->sk;



		bh_lock_sock(sk);
@@ -4608,7 +4605,7 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt) 
		bh_unlock_sock(sk);

	}



	mutex_unlock(&conn->chan_lock);

	rcu_read_unlock();



	return 0;

}