Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 347 insertions, 295 deletions

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 32d338c30e6..b8e17e4dac8 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -49,7 +49,6 @@
 #include <linux/crc16.h>
 #include <net/sock.h>
 
-#include <asm/system.h>
 #include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -73,42 +72,28 @@ static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data);
 static void l2cap_send_disconn_req(struct l2cap_conn *conn,
 				struct l2cap_chan *chan, int err);
 
-static int l2cap_ertm_data_rcv(struct sock *sk, struct sk_buff *skb);
-
 /* ---- L2CAP channels ---- */
 
 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.
@@ -117,36 +102,32 @@ 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;
 }
 
@@ -217,51 +198,51 @@ static u16 l2cap_alloc_cid(struct l2cap_conn *conn)
 	return 0;
 }
 
-static char *state_to_string(int state)
+static void __l2cap_state_change(struct l2cap_chan *chan, int state)
 {
-	switch(state) {
-	case BT_CONNECTED:
-		return "BT_CONNECTED";
-	case BT_OPEN:
-		return "BT_OPEN";
-	case BT_BOUND:
-		return "BT_BOUND";
-	case BT_LISTEN:
-		return "BT_LISTEN";
-	case BT_CONNECT:
-		return "BT_CONNECT";
-	case BT_CONNECT2:
-		return "BT_CONNECT2";
-	case BT_CONFIG:
-		return "BT_CONFIG";
-	case BT_DISCONN:
-		return "BT_DISCONN";
-	case BT_CLOSED:
-		return "BT_CLOSED";
-	}
+	BT_DBG("chan %p %s -> %s", chan, state_to_string(chan->state),
+						state_to_string(state));
 
-	return "invalid state";
+	chan->state = state;
+	chan->ops->state_change(chan->data, state);
 }
 
 static void l2cap_state_change(struct l2cap_chan *chan, int state)
 {
-	BT_DBG("%p %s -> %s", chan, state_to_string(chan->state),
-						state_to_string(state));
+	struct sock *sk = chan->sk;
 
-	chan->state = state;
-	chan->ops->state_change(chan->data, state);
+	lock_sock(sk);
+	__l2cap_state_change(chan, state);
+	release_sock(sk);
+}
+
+static inline void __l2cap_chan_set_err(struct l2cap_chan *chan, int err)
+{
+	struct sock *sk = chan->sk;
+
+	sk->sk_err = err;
+}
+
+static inline void l2cap_chan_set_err(struct l2cap_chan *chan, int err)
+{
+	struct sock *sk = chan->sk;
+
+	lock_sock(sk);
+	__l2cap_chan_set_err(chan, err);
+	release_sock(sk);
 }
 
 static void l2cap_chan_timeout(struct work_struct *work)
 {
 	struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
 							chan_timer.work);
-	struct sock *sk = chan->sk;
+	struct l2cap_conn *conn = chan->conn;
 	int reason;
 
-	BT_DBG("chan %p state %d", chan, chan->state);
+	BT_DBG("chan %p state %s", chan, state_to_string(chan->state));
 
-	lock_sock(sk);
+	mutex_lock(&conn->chan_lock);
+	l2cap_chan_lock(chan);
 
 	if (chan->state == BT_CONNECTED || chan->state == BT_CONFIG)
 		reason = ECONNREFUSED;
@@ -273,9 +254,11 @@ static void l2cap_chan_timeout(struct work_struct *work)
 
 	l2cap_chan_close(chan, reason);
 
-	release_sock(sk);
+	l2cap_chan_unlock(chan);
 
 	chan->ops->close(chan->data);
+	mutex_unlock(&conn->chan_lock);
+
 	l2cap_chan_put(chan);
 }
 
@@ -287,6 +270,8 @@ struct l2cap_chan *l2cap_chan_create(struct sock *sk)
 	if (!chan)
 		return NULL;
 
+	mutex_init(&chan->lock);
+
 	chan->sk = sk;
 
 	write_lock(&chan_list_lock);
@@ -313,7 +298,7 @@ void l2cap_chan_destroy(struct l2cap_chan *chan)
 	l2cap_chan_put(chan);
 }
 
-static void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
+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);
@@ -322,7 +307,8 @@ static void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
 
 	chan->conn = conn;
 
-	if (chan->chan_type == L2CAP_CHAN_CONN_ORIENTED) {
+	switch (chan->chan_type) {
+	case L2CAP_CHAN_CONN_ORIENTED:
 		if (conn->hcon->type == LE_LINK) {
 			/* LE connection */
 			chan->omtu = L2CAP_LE_DEFAULT_MTU;
@@ -333,12 +319,16 @@ static void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
 			chan->scid = l2cap_alloc_cid(conn);
 			chan->omtu = L2CAP_DEFAULT_MTU;
 		}
-	} else if (chan->chan_type == L2CAP_CHAN_CONN_LESS) {
+		break;
+
+	case L2CAP_CHAN_CONN_LESS:
 		/* Connectionless socket */
 		chan->scid = L2CAP_CID_CONN_LESS;
 		chan->dcid = L2CAP_CID_CONN_LESS;
 		chan->omtu = L2CAP_DEFAULT_MTU;
-	} else {
+		break;
+
+	default:
 		/* Raw socket can send/recv signalling messages only */
 		chan->scid = L2CAP_CID_SIGNALING;
 		chan->dcid = L2CAP_CID_SIGNALING;
@@ -354,11 +344,16 @@ 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);
+	list_add(&chan->list, &conn->chan_l);
+}
+
+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);
 }
 
-/* Delete channel.
- * Must be called on the locked socket. */
 static void l2cap_chan_del(struct l2cap_chan *chan, int err)
 {
 	struct sock *sk = chan->sk;
@@ -371,8 +366,7 @@ 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);
 
@@ -380,11 +374,13 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
 		hci_conn_put(conn->hcon);
 	}
 
-	l2cap_state_change(chan, BT_CLOSED);
+	lock_sock(sk);
+
+	__l2cap_state_change(chan, BT_CLOSED);
 	sock_set_flag(sk, SOCK_ZAPPED);
 
 	if (err)
-		sk->sk_err = err;
+		__l2cap_chan_set_err(chan, err);
 
 	if (parent) {
 		bt_accept_unlink(sk);
@@ -392,6 +388,8 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
 	} else
 		sk->sk_state_change(sk);
 
+	release_sock(sk);
+
 	if (!(test_bit(CONF_OUTPUT_DONE, &chan->conf_state) &&
 			test_bit(CONF_INPUT_DONE, &chan->conf_state)))
 		return;
@@ -423,10 +421,12 @@ 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;
+
+		l2cap_chan_lock(chan);
 		__clear_chan_timer(chan);
-		lock_sock(sk);
 		l2cap_chan_close(chan, ECONNRESET);
-		release_sock(sk);
+		l2cap_chan_unlock(chan);
+
 		chan->ops->close(chan->data);
 	}
 }
@@ -436,14 +436,17 @@ void l2cap_chan_close(struct l2cap_chan *chan, int reason)
 	struct l2cap_conn *conn = chan->conn;
 	struct sock *sk = chan->sk;
 
-	BT_DBG("chan %p state %d socket %p", chan, chan->state, sk->sk_socket);
+	BT_DBG("chan %p state %s sk %p", chan,
+					state_to_string(chan->state), sk);
 
 	switch (chan->state) {
 	case BT_LISTEN:
+		lock_sock(sk);
 		l2cap_chan_cleanup_listen(sk);
 
-		l2cap_state_change(chan, BT_CLOSED);
+		__l2cap_state_change(chan, BT_CLOSED);
 		sock_set_flag(sk, SOCK_ZAPPED);
+		release_sock(sk);
 		break;
 
 	case BT_CONNECTED:
@@ -486,7 +489,9 @@ void l2cap_chan_close(struct l2cap_chan *chan, int reason)
 		break;
 
 	default:
+		lock_sock(sk);
 		sock_set_flag(sk, SOCK_ZAPPED);
+		release_sock(sk);
 		break;
 	}
 }
@@ -661,6 +666,21 @@ static inline int __l2cap_no_conn_pending(struct l2cap_chan *chan)
 	return !test_bit(CONF_CONNECT_PEND, &chan->conf_state);
 }
 
+static void l2cap_send_conn_req(struct l2cap_chan *chan)
+{
+	struct l2cap_conn *conn = chan->conn;
+	struct l2cap_conn_req req;
+
+	req.scid = cpu_to_le16(chan->scid);
+	req.psm  = chan->psm;
+
+	chan->ident = l2cap_get_ident(conn);
+
+	set_bit(CONF_CONNECT_PEND, &chan->conf_state);
+
+	l2cap_send_cmd(conn, chan->ident, L2CAP_CONN_REQ, sizeof(req), &req);
+}
+
 static void l2cap_do_start(struct l2cap_chan *chan)
 {
 	struct l2cap_conn *conn = chan->conn;
@@ -670,17 +690,8 @@ static void l2cap_do_start(struct l2cap_chan *chan)
 			return;
 
 		if (l2cap_chan_check_security(chan) &&
-				__l2cap_no_conn_pending(chan)) {
-			struct l2cap_conn_req req;
-			req.scid = cpu_to_le16(chan->scid);
-			req.psm  = chan->psm;
-
-			chan->ident = l2cap_get_ident(conn);
-			set_bit(CONF_CONNECT_PEND, &chan->conf_state);
-
-			l2cap_send_cmd(conn, chan->ident, L2CAP_CONN_REQ,
-							sizeof(req), &req);
-		}
+				__l2cap_no_conn_pending(chan))
+			l2cap_send_conn_req(chan);
 	} else {
 		struct l2cap_info_req req;
 		req.type = cpu_to_le16(L2CAP_IT_FEAT_MASK);
@@ -688,8 +699,7 @@ static void l2cap_do_start(struct l2cap_chan *chan)
 		conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_SENT;
 		conn->info_ident = l2cap_get_ident(conn);
 
-		schedule_delayed_work(&conn->info_timer,
-					msecs_to_jiffies(L2CAP_INFO_TIMEOUT));
+		schedule_delayed_work(&conn->info_timer, L2CAP_INFO_TIMEOUT);
 
 		l2cap_send_cmd(conn, conn->info_ident,
 					L2CAP_INFO_REQ, sizeof(req), &req);
@@ -714,14 +724,12 @@ static inline int l2cap_mode_supported(__u8 mode, __u32 feat_mask)
 
 static void l2cap_send_disconn_req(struct l2cap_conn *conn, struct l2cap_chan *chan, int err)
 {
-	struct sock *sk;
+	struct sock *sk = chan->sk;
 	struct l2cap_disconn_req req;
 
 	if (!conn)
 		return;
 
-	sk = chan->sk;
-
 	if (chan->mode == L2CAP_MODE_ERTM) {
 		__clear_retrans_timer(chan);
 		__clear_monitor_timer(chan);
@@ -733,56 +741,47 @@ static void l2cap_send_disconn_req(struct l2cap_conn *conn, struct l2cap_chan *c
 	l2cap_send_cmd(conn, l2cap_get_ident(conn),
 			L2CAP_DISCONN_REQ, sizeof(req), &req);
 
-	l2cap_state_change(chan, BT_DISCONN);
-	sk->sk_err = err;
+	lock_sock(sk);
+	__l2cap_state_change(chan, BT_DISCONN);
+	__l2cap_chan_set_err(chan, err);
+	release_sock(sk);
 }
 
 /* ---- 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);
+		l2cap_chan_lock(chan);
 
 		if (chan->chan_type != L2CAP_CHAN_CONN_ORIENTED) {
-			bh_unlock_sock(sk);
+			l2cap_chan_unlock(chan);
 			continue;
 		}
 
 		if (chan->state == BT_CONNECT) {
-			struct l2cap_conn_req req;
-
 			if (!l2cap_chan_check_security(chan) ||
 					!__l2cap_no_conn_pending(chan)) {
-				bh_unlock_sock(sk);
+				l2cap_chan_unlock(chan);
 				continue;
 			}
 
 			if (!l2cap_mode_supported(chan->mode, conn->feat_mask)
 					&& test_bit(CONF_STATE2_DEVICE,
 					&chan->conf_state)) {
-				/* l2cap_chan_close() calls list_del(chan)
-				 * so release the lock */
 				l2cap_chan_close(chan, ECONNRESET);
-				bh_unlock_sock(sk);
+				l2cap_chan_unlock(chan);
 				continue;
 			}
 
-			req.scid = cpu_to_le16(chan->scid);
-			req.psm  = chan->psm;
-
-			chan->ident = l2cap_get_ident(conn);
-			set_bit(CONF_CONNECT_PEND, &chan->conf_state);
-
-			l2cap_send_cmd(conn, chan->ident, L2CAP_CONN_REQ,
-							sizeof(req), &req);
+			l2cap_send_conn_req(chan);
 
 		} else if (chan->state == BT_CONNECT2) {
 			struct l2cap_conn_rsp rsp;
@@ -791,6 +790,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
 			rsp.dcid = cpu_to_le16(chan->scid);
 
 			if (l2cap_chan_check_security(chan)) {
+				lock_sock(sk);
 				if (bt_sk(sk)->defer_setup) {
 					struct sock *parent = bt_sk(sk)->parent;
 					rsp.result = cpu_to_le16(L2CAP_CR_PEND);
@@ -799,10 +799,11 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
 						parent->sk_data_ready(parent, 0);
 
 				} else {
-					l2cap_state_change(chan, BT_CONFIG);
+					__l2cap_state_change(chan, BT_CONFIG);
 					rsp.result = cpu_to_le16(L2CAP_CR_SUCCESS);
 					rsp.status = cpu_to_le16(L2CAP_CS_NO_INFO);
 				}
+				release_sock(sk);
 			} else {
 				rsp.result = cpu_to_le16(L2CAP_CR_PEND);
 				rsp.status = cpu_to_le16(L2CAP_CS_AUTHEN_PEND);
@@ -813,7 +814,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
 
 			if (test_bit(CONF_REQ_SENT, &chan->conf_state) ||
 					rsp.result != L2CAP_CR_SUCCESS) {
-				bh_unlock_sock(sk);
+				l2cap_chan_unlock(chan);
 				continue;
 			}
 
@@ -823,10 +824,10 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
 			chan->num_conf_req++;
 		}
 
-		bh_unlock_sock(sk);
+		l2cap_chan_unlock(chan);
 	}
 
-	rcu_read_unlock();
+	mutex_unlock(&conn->chan_lock);
 }
 
 /* Find socket with cid and source bdaddr.
@@ -902,28 +903,34 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn)
 
 	__set_chan_timer(chan, sk->sk_sndtimeo);
 
-	l2cap_state_change(chan, BT_CONNECTED);
+	__l2cap_state_change(chan, BT_CONNECTED);
 	parent->sk_data_ready(parent, 0);
 
 clean:
 	release_sock(parent);
 }
 
-static void l2cap_chan_ready(struct sock *sk)
+static void l2cap_chan_ready(struct l2cap_chan *chan)
 {
-	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
-	struct sock *parent = bt_sk(sk)->parent;
+	struct sock *sk = chan->sk;
+	struct sock *parent;
+
+	lock_sock(sk);
+
+	parent = bt_sk(sk)->parent;
 
 	BT_DBG("sk %p, parent %p", sk, parent);
 
 	chan->conf_state = 0;
 	__clear_chan_timer(chan);
 
-	l2cap_state_change(chan, BT_CONNECTED);
+	__l2cap_state_change(chan, BT_CONNECTED);
 	sk->sk_state_change(sk);
 
 	if (parent)
 		parent->sk_data_ready(parent, 0);
+
+	release_sock(sk);
 }
 
 static void l2cap_conn_ready(struct l2cap_conn *conn)
@@ -938,29 +945,31 @@ 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) {
-		struct sock *sk = chan->sk;
+	list_for_each_entry(chan, &conn->chan_l, list) {
 
-		bh_lock_sock(sk);
+		l2cap_chan_lock(chan);
 
 		if (conn->hcon->type == LE_LINK) {
 			if (smp_conn_security(conn, chan->sec_level))
-				l2cap_chan_ready(sk);
+				l2cap_chan_ready(chan);
 
 		} else if (chan->chan_type != L2CAP_CHAN_CONN_ORIENTED) {
+			struct sock *sk = chan->sk;
 			__clear_chan_timer(chan);
-			l2cap_state_change(chan, BT_CONNECTED);
+			lock_sock(sk);
+			__l2cap_state_change(chan, BT_CONNECTED);
 			sk->sk_state_change(sk);
+			release_sock(sk);
 
 		} else if (chan->state == BT_CONNECT)
 			l2cap_do_start(chan);
 
-		bh_unlock_sock(sk);
+		l2cap_chan_unlock(chan);
 	}
 
-	rcu_read_unlock();
+	mutex_unlock(&conn->chan_lock);
 }
 
 /* Notify sockets that we cannot guaranty reliability anymore */
@@ -970,16 +979,14 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
 
 	BT_DBG("conn %p", conn);
 
-	rcu_read_lock();
-
-	list_for_each_entry_rcu(chan, &conn->chan_l, list) {
-		struct sock *sk = chan->sk;
+	mutex_lock(&conn->chan_lock);
 
+	list_for_each_entry(chan, &conn->chan_l, list) {
 		if (test_bit(FLAG_FORCE_RELIABLE, &chan->flags))
-			sk->sk_err = err;
+			__l2cap_chan_set_err(chan, err);
 	}
 
-	rcu_read_unlock();
+	mutex_unlock(&conn->chan_lock);
 }
 
 static void l2cap_info_timeout(struct work_struct *work)
@@ -997,7 +1004,6 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
 {
 	struct l2cap_conn *conn = hcon->l2cap_data;
 	struct l2cap_chan *chan, *l;
-	struct sock *sk;
 
 	if (!conn)
 		return;
@@ -1006,21 +1012,27 @@ 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;
-		lock_sock(sk);
+		l2cap_chan_lock(chan);
+
 		l2cap_chan_del(chan, err);
-		release_sock(sk);
+
+		l2cap_chan_unlock(chan);
+
 		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)
 		cancel_delayed_work_sync(&conn->info_timer);
 
-	if (test_and_clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->pend)) {
+	if (test_and_clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags)) {
 		cancel_delayed_work_sync(&conn->security_timer);
 		smp_chan_destroy(conn);
 	}
@@ -1072,6 +1084,7 @@ 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);
 
@@ -1139,7 +1152,7 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, bdaddr_t *d
 
 	hci_dev_lock(hdev);
 
-	lock_sock(sk);
+	l2cap_chan_lock(chan);
 
 	/* PSM must be odd and lsb of upper byte must be 0 */
 	if ((__le16_to_cpu(psm) & 0x0101) != 0x0001 && !cid &&
@@ -1166,17 +1179,21 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, bdaddr_t *d
 		goto done;
 	}
 
+	lock_sock(sk);
+
 	switch (sk->sk_state) {
 	case BT_CONNECT:
 	case BT_CONNECT2:
 	case BT_CONFIG:
 		/* Already connecting */
 		err = 0;
+		release_sock(sk);
 		goto done;
 
 	case BT_CONNECTED:
 		/* Already connected */
 		err = -EISCONN;
+		release_sock(sk);
 		goto done;
 
 	case BT_OPEN:
@@ -1186,11 +1203,15 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, bdaddr_t *d
 
 	default:
 		err = -EBADFD;
+		release_sock(sk);
 		goto done;
 	}
 
 	/* Set destination address and psm */
 	bacpy(&bt_sk(sk)->dst, dst);
+
+	release_sock(sk);
+
 	chan->psm = psm;
 	chan->dcid = cid;
 
@@ -1218,7 +1239,9 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, bdaddr_t *d
 	/* Update source addr of the socket */
 	bacpy(src, conn->src);
 
+	l2cap_chan_unlock(chan);
 	l2cap_chan_add(conn, chan);
+	l2cap_chan_lock(chan);
 
 	l2cap_state_change(chan, BT_CONNECT);
 	__set_chan_timer(chan, sk->sk_sndtimeo);
@@ -1235,6 +1258,7 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, bdaddr_t *d
 	err = 0;
 
 done:
+	l2cap_chan_unlock(chan);
 	hci_dev_unlock(hdev);
 	hci_dev_put(hdev);
 	return err;
@@ -1276,14 +1300,14 @@ static void l2cap_monitor_timeout(struct work_struct *work)
 {
 	struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
 							monitor_timer.work);
-	struct sock *sk = chan->sk;
 
 	BT_DBG("chan %p", chan);
 
-	lock_sock(sk);
+	l2cap_chan_lock(chan);
+
 	if (chan->retry_count >= chan->remote_max_tx) {
 		l2cap_send_disconn_req(chan->conn, chan, ECONNABORTED);
-		release_sock(sk);
+		l2cap_chan_unlock(chan);
 		return;
 	}
 
@@ -1291,25 +1315,26 @@ static void l2cap_monitor_timeout(struct work_struct *work)
 	__set_monitor_timer(chan);
 
 	l2cap_send_rr_or_rnr(chan, L2CAP_CTRL_POLL);
-	release_sock(sk);
+	l2cap_chan_unlock(chan);
 }
 
 static void l2cap_retrans_timeout(struct work_struct *work)
 {
 	struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
 							retrans_timer.work);
-	struct sock *sk = chan->sk;
 
 	BT_DBG("chan %p", chan);
 
-	lock_sock(sk);
+	l2cap_chan_lock(chan);
+
 	chan->retry_count = 1;
 	__set_monitor_timer(chan);
 
 	set_bit(CONN_WAIT_F, &chan->conn_state);
 
 	l2cap_send_rr_or_rnr(chan, L2CAP_CTRL_POLL);
-	release_sock(sk);
+
+	l2cap_chan_unlock(chan);
 }
 
 static void l2cap_drop_acked_frames(struct l2cap_chan *chan)
@@ -1450,17 +1475,19 @@ static int l2cap_ertm_send(struct l2cap_chan *chan)
 
 		chan->next_tx_seq = __next_seq(chan, chan->next_tx_seq);
 
-		if (bt_cb(skb)->retries == 1)
+		if (bt_cb(skb)->retries == 1) {
 			chan->unacked_frames++;
 
+			if (!nsent++)
+				__clear_ack_timer(chan);
+		}
+
 		chan->frames_sent++;
 
 		if (skb_queue_is_last(&chan->tx_q, skb))
 			chan->tx_send_head = NULL;
 		else
 			chan->tx_send_head = skb_queue_next(&chan->tx_q, skb);
-
-		nsent++;
 	}
 
 	return nsent;
@@ -1478,7 +1505,7 @@ static int l2cap_retransmit_frames(struct l2cap_chan *chan)
 	return ret;
 }
 
-static void l2cap_send_ack(struct l2cap_chan *chan)
+static void __l2cap_send_ack(struct l2cap_chan *chan)
 {
 	u32 control = 0;
 
@@ -1498,6 +1525,12 @@ static void l2cap_send_ack(struct l2cap_chan *chan)
 	l2cap_send_sframe(chan, control);
 }
 
+static void l2cap_send_ack(struct l2cap_chan *chan)
+{
+	__clear_ack_timer(chan);
+	__l2cap_send_ack(chan);
+}
+
 static void l2cap_send_srejtail(struct l2cap_chan *chan)
 {
 	struct srej_list *tail;
@@ -1512,9 +1545,11 @@ static void l2cap_send_srejtail(struct l2cap_chan *chan)
 	l2cap_send_sframe(chan, control);
 }
 
-static inline int l2cap_skbuff_fromiovec(struct sock *sk, struct msghdr *msg, int len, int count, struct sk_buff *skb)
+static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan,
+					 struct msghdr *msg, int len,
+					 int count, struct sk_buff *skb)
 {
-	struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
+	struct l2cap_conn *conn = chan->conn;
 	struct sk_buff **frag;
 	int err, sent = 0;
 
@@ -1529,7 +1564,10 @@ static inline int l2cap_skbuff_fromiovec(struct sock *sk, struct msghdr *msg, in
 	while (len) {
 		count = min_t(unsigned int, conn->mtu, len);
 
-		*frag = bt_skb_send_alloc(sk, count, msg->msg_flags & MSG_DONTWAIT, &err);
+		*frag = chan->ops->alloc_skb(chan, count,
+					     msg->msg_flags & MSG_DONTWAIT,
+					     &err);
+
 		if (!*frag)
 			return err;
 		if (memcpy_fromiovec(skb_put(*frag, count), msg->msg_iov, count))
@@ -1550,17 +1588,18 @@ static struct sk_buff *l2cap_create_connless_pdu(struct l2cap_chan *chan,
 						struct msghdr *msg, size_t len,
 						u32 priority)
 {
-	struct sock *sk = chan->sk;
 	struct l2cap_conn *conn = chan->conn;
 	struct sk_buff *skb;
 	int err, count, hlen = L2CAP_HDR_SIZE + L2CAP_PSMLEN_SIZE;
 	struct l2cap_hdr *lh;
 
-	BT_DBG("sk %p len %d priority %u", sk, (int)len, priority);
+	BT_DBG("chan %p len %d priority %u", chan, (int)len, priority);
 
 	count = min_t(unsigned int, (conn->mtu - hlen), len);
-	skb = bt_skb_send_alloc(sk, count + hlen,
-			msg->msg_flags & MSG_DONTWAIT, &err);
+
+	skb = chan->ops->alloc_skb(chan, count + hlen,
+				   msg->msg_flags & MSG_DONTWAIT, &err);
+
 	if (!skb)
 		return ERR_PTR(err);
 
@@ -1572,7 +1611,7 @@ static struct sk_buff *l2cap_create_connless_pdu(struct l2cap_chan *chan,
 	lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
 	put_unaligned_le16(chan->psm, skb_put(skb, 2));
 
-	err = l2cap_skbuff_fromiovec(sk, msg, len, count, skb);
+	err = l2cap_skbuff_fromiovec(chan, msg, len, count, skb);
 	if (unlikely(err < 0)) {
 		kfree_skb(skb);
 		return ERR_PTR(err);
@@ -1584,17 +1623,18 @@ static struct sk_buff *l2cap_create_basic_pdu(struct l2cap_chan *chan,
 						struct msghdr *msg, size_t len,
 						u32 priority)
 {
-	struct sock *sk = chan->sk;
 	struct l2cap_conn *conn = chan->conn;
 	struct sk_buff *skb;
 	int err, count, hlen = L2CAP_HDR_SIZE;
 	struct l2cap_hdr *lh;
 
-	BT_DBG("sk %p len %d", sk, (int)len);
+	BT_DBG("chan %p len %d", chan, (int)len);
 
 	count = min_t(unsigned int, (conn->mtu - hlen), len);
-	skb = bt_skb_send_alloc(sk, count + hlen,
-			msg->msg_flags & MSG_DONTWAIT, &err);
+
+	skb = chan->ops->alloc_skb(chan, count + hlen,
+				   msg->msg_flags & MSG_DONTWAIT, &err);
+
 	if (!skb)
 		return ERR_PTR(err);
 
@@ -1605,7 +1645,7 @@ static struct sk_buff *l2cap_create_basic_pdu(struct l2cap_chan *chan,
 	lh->cid = cpu_to_le16(chan->dcid);
 	lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
 
-	err = l2cap_skbuff_fromiovec(sk, msg, len, count, skb);
+	err = l2cap_skbuff_fromiovec(chan, msg, len, count, skb);
 	if (unlikely(err < 0)) {
 		kfree_skb(skb);
 		return ERR_PTR(err);
@@ -1617,13 +1657,12 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
 						struct msghdr *msg, size_t len,
 						u32 control, u16 sdulen)
 {
-	struct sock *sk = chan->sk;
 	struct l2cap_conn *conn = chan->conn;
 	struct sk_buff *skb;
 	int err, count, hlen;
 	struct l2cap_hdr *lh;
 
-	BT_DBG("sk %p len %d", sk, (int)len);
+	BT_DBG("chan %p len %d", chan, (int)len);
 
 	if (!conn)
 		return ERR_PTR(-ENOTCONN);
@@ -1640,8 +1679,10 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
 		hlen += L2CAP_FCS_SIZE;
 
 	count = min_t(unsigned int, (conn->mtu - hlen), len);
-	skb = bt_skb_send_alloc(sk, count + hlen,
-			msg->msg_flags & MSG_DONTWAIT, &err);
+
+	skb = chan->ops->alloc_skb(chan, count + hlen,
+					msg->msg_flags & MSG_DONTWAIT, &err);
+
 	if (!skb)
 		return ERR_PTR(err);
 
@@ -1655,7 +1696,7 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
 	if (sdulen)
 		put_unaligned_le16(sdulen, skb_put(skb, L2CAP_SDULEN_SIZE));
 
-	err = l2cap_skbuff_fromiovec(sk, msg, len, count, skb);
+	err = l2cap_skbuff_fromiovec(chan, msg, len, count, skb);
 	if (unlikely(err < 0)) {
 		kfree_skb(skb);
 		return ERR_PTR(err);
@@ -1801,9 +1842,9 @@ 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;
@@ -1819,7 +1860,7 @@ 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 ---- */
@@ -1987,9 +2028,13 @@ static void l2cap_ack_timeout(struct work_struct *work)
 
 	BT_DBG("chan %p", chan);
 
-	lock_sock(chan->sk);
-	l2cap_send_ack(chan);
-	release_sock(chan->sk);
+	l2cap_chan_lock(chan);
+
+	__l2cap_send_ack(chan);
+
+	l2cap_chan_unlock(chan);
+
+	l2cap_chan_put(chan);
 }
 
 static inline void l2cap_ertm_init(struct l2cap_chan *chan)
@@ -2607,6 +2652,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
 
 	parent = pchan->sk;
 
+	mutex_lock(&conn->chan_lock);
 	lock_sock(parent);
 
 	/* Check if the ACL is secure enough (if not SDP) */
@@ -2647,7 +2693,7 @@ 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;
 
@@ -2658,28 +2704,29 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
 	if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE) {
 		if (l2cap_chan_check_security(chan)) {
 			if (bt_sk(sk)->defer_setup) {
-				l2cap_state_change(chan, BT_CONNECT2);
+				__l2cap_state_change(chan, BT_CONNECT2);
 				result = L2CAP_CR_PEND;
 				status = L2CAP_CS_AUTHOR_PEND;
 				parent->sk_data_ready(parent, 0);
 			} else {
-				l2cap_state_change(chan, BT_CONFIG);
+				__l2cap_state_change(chan, BT_CONFIG);
 				result = L2CAP_CR_SUCCESS;
 				status = L2CAP_CS_NO_INFO;
 			}
 		} else {
-			l2cap_state_change(chan, BT_CONNECT2);
+			__l2cap_state_change(chan, BT_CONNECT2);
 			result = L2CAP_CR_PEND;
 			status = L2CAP_CS_AUTHEN_PEND;
 		}
 	} else {
-		l2cap_state_change(chan, BT_CONNECT2);
+		__l2cap_state_change(chan, BT_CONNECT2);
 		result = L2CAP_CR_PEND;
 		status = L2CAP_CS_NO_INFO;
 	}
 
 response:
 	release_sock(parent);
+	mutex_unlock(&conn->chan_lock);
 
 sendresp:
 	rsp.scid   = cpu_to_le16(scid);
@@ -2695,8 +2742,7 @@ sendresp:
 		conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_SENT;
 		conn->info_ident = l2cap_get_ident(conn);
 
-		schedule_delayed_work(&conn->info_timer,
-					msecs_to_jiffies(L2CAP_INFO_TIMEOUT));
+		schedule_delayed_work(&conn->info_timer, L2CAP_INFO_TIMEOUT);
 
 		l2cap_send_cmd(conn, conn->info_ident,
 					L2CAP_INFO_REQ, sizeof(info), &info);
@@ -2719,27 +2765,36 @@ static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hd
 	struct l2cap_conn_rsp *rsp = (struct l2cap_conn_rsp *) data;
 	u16 scid, dcid, result, status;
 	struct l2cap_chan *chan;
-	struct sock *sk;
 	u8 req[128];
+	int err;
 
 	scid   = __le16_to_cpu(rsp->scid);
 	dcid   = __le16_to_cpu(rsp->dcid);
 	result = __le16_to_cpu(rsp->result);
 	status = __le16_to_cpu(rsp->status);
 
-	BT_DBG("dcid 0x%4.4x scid 0x%4.4x result 0x%2.2x status 0x%2.2x", dcid, scid, result, status);
+	BT_DBG("dcid 0x%4.4x scid 0x%4.4x result 0x%2.2x status 0x%2.2x",
+						dcid, scid, result, status);
+
+	mutex_lock(&conn->chan_lock);
 
 	if (scid) {
-		chan = l2cap_get_chan_by_scid(conn, scid);
-		if (!chan)
-			return -EFAULT;
+		chan = __l2cap_get_chan_by_scid(conn, scid);
+		if (!chan) {
+			err = -EFAULT;
+			goto unlock;
+		}
 	} else {
-		chan = l2cap_get_chan_by_ident(conn, cmd->ident);
-		if (!chan)
-			return -EFAULT;
+		chan = __l2cap_get_chan_by_ident(conn, cmd->ident);
+		if (!chan) {
+			err = -EFAULT;
+			goto unlock;
+		}
 	}
 
-	sk = chan->sk;
+	err = 0;
+
+	l2cap_chan_lock(chan);
 
 	switch (result) {
 	case L2CAP_CR_SUCCESS:
@@ -2765,8 +2820,12 @@ static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hd
 		break;
 	}
 
-	release_sock(sk);
-	return 0;
+	l2cap_chan_unlock(chan);
+
+unlock:
+	mutex_unlock(&conn->chan_lock);
+
+	return err;
 }
 
 static inline void set_default_fcs(struct l2cap_chan *chan)
@@ -2786,7 +2845,6 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	u16 dcid, flags;
 	u8 rsp[64];
 	struct l2cap_chan *chan;
-	struct sock *sk;
 	int len;
 
 	dcid  = __le16_to_cpu(req->dcid);
@@ -2798,7 +2856,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	if (!chan)
 		return -ENOENT;
 
-	sk = chan->sk;
+	l2cap_chan_lock(chan);
 
 	if (chan->state != BT_CONFIG && chan->state != BT_CONNECT2) {
 		struct l2cap_cmd_rej_cid rej;
@@ -2860,7 +2918,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 		if (chan->mode == L2CAP_MODE_ERTM)
 			l2cap_ertm_init(chan);
 
-		l2cap_chan_ready(sk);
+		l2cap_chan_ready(chan);
 		goto unlock;
 	}
 
@@ -2887,7 +2945,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	}
 
 unlock:
-	release_sock(sk);
+	l2cap_chan_unlock(chan);
 	return 0;
 }
 
@@ -2896,7 +2954,6 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	struct l2cap_conf_rsp *rsp = (struct l2cap_conf_rsp *)data;
 	u16 scid, flags, result;
 	struct l2cap_chan *chan;
-	struct sock *sk;
 	int len = cmd->len - sizeof(*rsp);
 
 	scid   = __le16_to_cpu(rsp->scid);
@@ -2910,7 +2967,7 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	if (!chan)
 		return 0;
 
-	sk = chan->sk;
+	l2cap_chan_lock(chan);
 
 	switch (result) {
 	case L2CAP_CONF_SUCCESS:
@@ -2969,9 +3026,9 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 		}
 
 	default:
-		sk->sk_err = ECONNRESET;
-		__set_chan_timer(chan,
-				msecs_to_jiffies(L2CAP_DISC_REJ_TIMEOUT));
+		l2cap_chan_set_err(chan, ECONNRESET);
+
+		__set_chan_timer(chan, L2CAP_DISC_REJ_TIMEOUT);
 		l2cap_send_disconn_req(conn, chan, ECONNRESET);
 		goto done;
 	}
@@ -2991,11 +3048,11 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 		if (chan->mode ==  L2CAP_MODE_ERTM)
 			l2cap_ertm_init(chan);
 
-		l2cap_chan_ready(sk);
+		l2cap_chan_ready(chan);
 	}
 
 done:
-	release_sock(sk);
+	l2cap_chan_unlock(chan);
 	return 0;
 }
 
@@ -3012,9 +3069,15 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
 
 	BT_DBG("scid 0x%4.4x dcid 0x%4.4x", scid, dcid);
 
-	chan = l2cap_get_chan_by_scid(conn, dcid);
-	if (!chan)
+	mutex_lock(&conn->chan_lock);
+
+	chan = __l2cap_get_chan_by_scid(conn, dcid);
+	if (!chan) {
+		mutex_unlock(&conn->chan_lock);
 		return 0;
+	}
+
+	l2cap_chan_lock(chan);
 
 	sk = chan->sk;
 
@@ -3022,12 +3085,18 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
 	rsp.scid = cpu_to_le16(chan->dcid);
 	l2cap_send_cmd(conn, cmd->ident, L2CAP_DISCONN_RSP, sizeof(rsp), &rsp);
 
+	lock_sock(sk);
 	sk->sk_shutdown = SHUTDOWN_MASK;
+	release_sock(sk);
 
 	l2cap_chan_del(chan, ECONNRESET);
-	release_sock(sk);
+
+	l2cap_chan_unlock(chan);
 
 	chan->ops->close(chan->data);
+
+	mutex_unlock(&conn->chan_lock);
+
 	return 0;
 }
 
@@ -3036,23 +3105,30 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd
 	struct l2cap_disconn_rsp *rsp = (struct l2cap_disconn_rsp *) data;
 	u16 dcid, scid;
 	struct l2cap_chan *chan;
-	struct sock *sk;
 
 	scid = __le16_to_cpu(rsp->scid);
 	dcid = __le16_to_cpu(rsp->dcid);
 
 	BT_DBG("dcid 0x%4.4x scid 0x%4.4x", dcid, scid);
 
-	chan = l2cap_get_chan_by_scid(conn, scid);
-	if (!chan)
+	mutex_lock(&conn->chan_lock);
+
+	chan = __l2cap_get_chan_by_scid(conn, scid);
+	if (!chan) {
+		mutex_unlock(&conn->chan_lock);
 		return 0;
+	}
 
-	sk = chan->sk;
+	l2cap_chan_lock(chan);
 
 	l2cap_chan_del(chan, 0);
-	release_sock(sk);
+
+	l2cap_chan_unlock(chan);
 
 	chan->ops->close(chan->data);
+
+	mutex_unlock(&conn->chan_lock);
+
 	return 0;
 }
 
@@ -3132,7 +3208,8 @@ static inline int l2cap_information_rsp(struct l2cap_conn *conn, struct l2cap_cm
 		return 0;
 	}
 
-	if (type == L2CAP_IT_FEAT_MASK) {
+	switch (type) {
+	case L2CAP_IT_FEAT_MASK:
 		conn->feat_mask = get_unaligned_le32(rsp->data);
 
 		if (conn->feat_mask & L2CAP_FEAT_FIXED_CHAN) {
@@ -3149,11 +3226,15 @@ static inline int l2cap_information_rsp(struct l2cap_conn *conn, struct l2cap_cm
 
 			l2cap_conn_start(conn);
 		}
-	} else if (type == L2CAP_IT_FIXED_CHAN) {
+		break;
+
+	case L2CAP_IT_FIXED_CHAN:
+		conn->fixed_chan_mask = rsp->data[0];
 		conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
 		conn->info_ident = 0;
 
 		l2cap_conn_start(conn);
+		break;
 	}
 
 	return 0;
@@ -3713,19 +3794,11 @@ static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u3
 
 static void l2cap_ertm_enter_local_busy(struct l2cap_chan *chan)
 {
-	u32 control;
-
 	BT_DBG("chan %p, Enter local busy", chan);
 
 	set_bit(CONN_LOCAL_BUSY, &chan->conn_state);
 
-	control = __set_reqseq(chan, chan->buffer_seq);
-	control |= __set_ctrl_super(chan, L2CAP_SUPER_RNR);
-	l2cap_send_sframe(chan, control);
-
-	set_bit(CONN_RNR_SENT, &chan->conn_state);
-
-	__clear_ack_timer(chan);
+	__set_ack_timer(chan);
 }
 
 static void l2cap_ertm_exit_local_busy(struct l2cap_chan *chan)
@@ -3865,8 +3938,11 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
 		goto drop;
 	}
 
-	if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state))
+	if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
+		if (!test_bit(CONN_RNR_SENT, &chan->conn_state))
+			l2cap_send_ack(chan);
 		goto drop;
+	}
 
 	if (tx_seq == chan->expected_tx_seq)
 		goto expected;
@@ -3927,15 +4003,15 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
 		__skb_queue_head_init(&chan->srej_q);
 		l2cap_add_to_srej_queue(chan, skb, tx_seq, sar);
 
-		set_bit(CONN_SEND_PBIT, &chan->conn_state);
+		/* Set P-bit only if there are some I-frames to ack. */
+		if (__clear_ack_timer(chan))
+			set_bit(CONN_SEND_PBIT, &chan->conn_state);
 
 		err = l2cap_send_srejframe(chan, tx_seq);
 		if (err < 0) {
 			l2cap_send_disconn_req(chan->conn, chan, -err);
 			return err;
 		}
-
-		__clear_ack_timer(chan);
 	}
 	return 0;
 
@@ -4135,9 +4211,8 @@ static inline int l2cap_data_channel_sframe(struct l2cap_chan *chan, u32 rx_cont
 	return 0;
 }
 
-static int l2cap_ertm_data_rcv(struct sock *sk, struct sk_buff *skb)
+static int l2cap_ertm_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
 {
-	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
 	u32 control;
 	u16 req_seq;
 	int len, next_tx_seq_offset, req_seq_offset;
@@ -4205,7 +4280,6 @@ drop:
 static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk_buff *skb)
 {
 	struct l2cap_chan *chan;
-	struct sock *sk = NULL;
 	u32 control;
 	u16 tx_seq;
 	int len;
@@ -4213,10 +4287,12 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
 	chan = l2cap_get_chan_by_scid(conn, cid);
 	if (!chan) {
 		BT_DBG("unknown cid 0x%4.4x", cid);
-		goto drop;
+		/* Drop packet and return */
+		kfree_skb(skb);
+		return 0;
 	}
 
-	sk = chan->sk;
+	l2cap_chan_lock(chan);
 
 	BT_DBG("chan %p, len %d", chan, skb->len);
 
@@ -4238,7 +4314,7 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
 		break;
 
 	case L2CAP_MODE_ERTM:
-		l2cap_ertm_data_rcv(sk, skb);
+		l2cap_ertm_data_rcv(chan, skb);
 
 		goto done;
 
@@ -4287,26 +4363,20 @@ drop:
 	kfree_skb(skb);
 
 done:
-	if (sk)
-		release_sock(sk);
+	l2cap_chan_unlock(chan);
 
 	return 0;
 }
 
 static inline int l2cap_conless_channel(struct l2cap_conn *conn, __le16 psm, struct sk_buff *skb)
 {
-	struct sock *sk = NULL;
 	struct l2cap_chan *chan;
 
 	chan = l2cap_global_chan_by_psm(0, psm, conn->src);
 	if (!chan)
 		goto drop;
 
-	sk = chan->sk;
-
-	lock_sock(sk);
-
-	BT_DBG("sk %p, len %d", sk, skb->len);
+	BT_DBG("chan %p, len %d", chan, skb->len);
 
 	if (chan->state != BT_BOUND && chan->state != BT_CONNECTED)
 		goto drop;
@@ -4315,31 +4385,23 @@ static inline int l2cap_conless_channel(struct l2cap_conn *conn, __le16 psm, str
 		goto drop;
 
 	if (!chan->ops->recv(chan->data, skb))
-		goto done;
+		return 0;
 
 drop:
 	kfree_skb(skb);
 
-done:
-	if (sk)
-		release_sock(sk);
 	return 0;
 }
 
 static inline int l2cap_att_channel(struct l2cap_conn *conn, __le16 cid, struct sk_buff *skb)
 {
-	struct sock *sk = NULL;
 	struct l2cap_chan *chan;
 
 	chan = l2cap_global_chan_by_scid(0, cid, conn->src);
 	if (!chan)
 		goto drop;
 
-	sk = chan->sk;
-
-	lock_sock(sk);
-
-	BT_DBG("sk %p, len %d", sk, skb->len);
+	BT_DBG("chan %p, len %d", chan, skb->len);
 
 	if (chan->state != BT_BOUND && chan->state != BT_CONNECTED)
 		goto drop;
@@ -4348,14 +4410,11 @@ static inline int l2cap_att_channel(struct l2cap_conn *conn, __le16 cid, struct
 		goto drop;
 
 	if (!chan->ops->recv(chan->data, skb))
-		goto done;
+		return 0;
 
 drop:
 	kfree_skb(skb);
 
-done:
-	if (sk)
-		release_sock(sk);
 	return 0;
 }
 
@@ -4479,8 +4538,7 @@ static inline void l2cap_check_encryption(struct l2cap_chan *chan, u8 encrypt)
 	if (encrypt == 0x00) {
 		if (chan->sec_level == BT_SECURITY_MEDIUM) {
 			__clear_chan_timer(chan);
-			__set_chan_timer(chan,
-					msecs_to_jiffies(L2CAP_ENC_TIMEOUT));
+			__set_chan_timer(chan, L2CAP_ENC_TIMEOUT);
 		} else if (chan->sec_level == BT_SECURITY_HIGH)
 			l2cap_chan_close(chan, ECONNREFUSED);
 	} else {
@@ -4504,57 +4562,49 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 		cancel_delayed_work(&conn->security_timer);
 	}
 
-	rcu_read_lock();
-
-	list_for_each_entry_rcu(chan, &conn->chan_l, list) {
-		struct sock *sk = chan->sk;
+	mutex_lock(&conn->chan_lock);
 
-		bh_lock_sock(sk);
+	list_for_each_entry(chan, &conn->chan_l, list) {
+		l2cap_chan_lock(chan);
 
 		BT_DBG("chan->scid %d", chan->scid);
 
 		if (chan->scid == L2CAP_CID_LE_DATA) {
 			if (!status && encrypt) {
 				chan->sec_level = hcon->sec_level;
-				l2cap_chan_ready(sk);
+				l2cap_chan_ready(chan);
 			}
 
-			bh_unlock_sock(sk);
+			l2cap_chan_unlock(chan);
 			continue;
 		}
 
 		if (test_bit(CONF_CONNECT_PEND, &chan->conf_state)) {
-			bh_unlock_sock(sk);
+			l2cap_chan_unlock(chan);
 			continue;
 		}
 
 		if (!status && (chan->state == BT_CONNECTED ||
 						chan->state == BT_CONFIG)) {
 			l2cap_check_encryption(chan, encrypt);
-			bh_unlock_sock(sk);
+			l2cap_chan_unlock(chan);
 			continue;
 		}
 
 		if (chan->state == BT_CONNECT) {
 			if (!status) {
-				struct l2cap_conn_req req;
-				req.scid = cpu_to_le16(chan->scid);
-				req.psm  = chan->psm;
-
-				chan->ident = l2cap_get_ident(conn);
-				set_bit(CONF_CONNECT_PEND, &chan->conf_state);
-
-				l2cap_send_cmd(conn, chan->ident,
-					L2CAP_CONN_REQ, sizeof(req), &req);
+				l2cap_send_conn_req(chan);
 			} else {
 				__clear_chan_timer(chan);
-				__set_chan_timer(chan,
-					msecs_to_jiffies(L2CAP_DISC_TIMEOUT));
+				__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
 			}
 		} else if (chan->state == BT_CONNECT2) {
+			struct sock *sk = chan->sk;
 			struct l2cap_conn_rsp rsp;
 			__u16 res, stat;
 
+			lock_sock(sk);
+
 			if (!status) {
 				if (bt_sk(sk)->defer_setup) {
 					struct sock *parent = bt_sk(sk)->parent;
@@ -4563,18 +4613,19 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 					if (parent)
 						parent->sk_data_ready(parent, 0);
 				} else {
-					l2cap_state_change(chan, BT_CONFIG);
+					__l2cap_state_change(chan, BT_CONFIG);
 					res = L2CAP_CR_SUCCESS;
 					stat = L2CAP_CS_NO_INFO;
 				}
 			} else {
-				l2cap_state_change(chan, BT_DISCONN);
-				__set_chan_timer(chan,
-					msecs_to_jiffies(L2CAP_DISC_TIMEOUT));
+				__l2cap_state_change(chan, BT_DISCONN);
+				__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
 				res = L2CAP_CR_SEC_BLOCK;
 				stat = L2CAP_CS_NO_INFO;
 			}
 
+			release_sock(sk);
+
 			rsp.scid   = cpu_to_le16(chan->dcid);
 			rsp.dcid   = cpu_to_le16(chan->scid);
 			rsp.result = cpu_to_le16(res);
@@ -4583,10 +4634,10 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 							sizeof(rsp), &rsp);
 		}
 
-		bh_unlock_sock(sk);
+		l2cap_chan_unlock(chan);
 	}
 
-	rcu_read_unlock();
+	mutex_unlock(&conn->chan_lock);
 
 	return 0;
 }
@@ -4647,6 +4698,7 @@ int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 
 		if (chan && chan->sk) {
 			struct sock *sk = chan->sk;
+			lock_sock(sk);
 
 			if (chan->imtu < len - L2CAP_HDR_SIZE) {
 				BT_ERR("Frame exceeding recv MTU (len %d, "
@@ -4717,7 +4769,7 @@ static int l2cap_debugfs_show(struct seq_file *f, void *p)
 					c->state, __le16_to_cpu(c->psm),
 					c->scid, c->dcid, c->imtu, c->omtu,
 					c->sec_level, c->mode);
-}
+	}
 
 	read_unlock(&chan_list_lock);