Bluetooth: Check rules when setting retransmit or monitor timers

The ERTM specification requires the retransmit timer to be cancelled
when the monitor timer is set.  The retransmit timer cannot be set
again while the monitor timer is pending.
Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

include/net/bluetooth/l2cap.h

@@ -706,11 +706,7 @@ static inline bool l2cap_clear_timer(struct l2cap_chan *chan,
 
 #define __set_chan_timer(c, t) l2cap_set_timer(c, &c->chan_timer, (t))
 #define __clear_chan_timer(c) l2cap_clear_timer(c, &c->chan_timer)
-#define __set_retrans_timer(c) l2cap_set_timer(c, &c->retrans_timer, \
-		msecs_to_jiffies(L2CAP_DEFAULT_RETRANS_TO));
 #define __clear_retrans_timer(c) l2cap_clear_timer(c, &c->retrans_timer)
-#define __set_monitor_timer(c) l2cap_set_timer(c, &c->monitor_timer, \
-		msecs_to_jiffies(L2CAP_DEFAULT_MONITOR_TO));
 #define __clear_monitor_timer(c) l2cap_clear_timer(c, &c->monitor_timer)
 #define __set_ack_timer(c) l2cap_set_timer(c, &chan->ack_timer, \
 		msecs_to_jiffies(L2CAP_DEFAULT_ACK_TO));

net/bluetooth/l2cap_core.c

@@ -227,6 +227,24 @@ static inline void l2cap_chan_set_err(struct l2cap_chan *chan, int err)
 	release_sock(sk);
 }
 
+static void __set_retrans_timer(struct l2cap_chan *chan)
+{
+	if (!delayed_work_pending(&chan->monitor_timer) &&
+	    chan->retrans_timeout) {
+		l2cap_set_timer(chan, &chan->retrans_timer,
+				msecs_to_jiffies(chan->retrans_timeout));
+	}
+}
+
+static void __set_monitor_timer(struct l2cap_chan *chan)
+{
+	__clear_retrans_timer(chan);
+	if (chan->monitor_timeout) {
+		l2cap_set_timer(chan, &chan->monitor_timer,
+				msecs_to_jiffies(chan->monitor_timeout));
+	}
+}
+
 static struct sk_buff *l2cap_ertm_seq_in_queue(struct sk_buff_head *head,
 					       u16 seq)
 {