Bluetooth: Introduce L2CAP channel callback for suspending

Setting the BT_SK_SUSPEND socket flag from the L2CAP core is causing a
dependency on the socket. So instead of doing that, use a channel
callback into the socket handling to suspend.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/l2cap.h

@@ -593,6 +593,7 @@ struct l2cap_ops {
 	void			(*ready) (struct l2cap_chan *chan);
 	void			(*defer) (struct l2cap_chan *chan);
 	void			(*resume) (struct l2cap_chan *chan);
+	void			(*suspend) (struct l2cap_chan *chan);
 	void			(*set_shutdown) (struct l2cap_chan *chan);
 	long			(*get_sndtimeo) (struct l2cap_chan *chan);
 	struct sk_buff		*(*alloc_skb) (struct l2cap_chan *chan,

net/bluetooth/l2cap_sock.c

@@ -1345,6 +1345,14 @@ static long l2cap_sock_get_sndtimeo_cb(struct l2cap_chan *chan)
 	return sk->sk_sndtimeo;
 }
 
+static void l2cap_sock_suspend_cb(struct l2cap_chan *chan)
+{
+	struct sock *sk = chan->data;
+
+	set_bit(BT_SK_SUSPEND, &bt_sk(sk)->flags);
+	sk->sk_state_change(sk);
+}
+
 static struct l2cap_ops l2cap_chan_ops = {
 	.name		= "L2CAP Socket Interface",
 	.new_connection	= l2cap_sock_new_connection_cb,
@@ -1355,6 +1363,7 @@ static struct l2cap_ops l2cap_chan_ops = {
 	.ready		= l2cap_sock_ready_cb,
 	.defer		= l2cap_sock_defer_cb,
 	.resume		= l2cap_sock_resume_cb,
+	.suspend	= l2cap_sock_suspend_cb,
 	.set_shutdown	= l2cap_sock_set_shutdown_cb,
 	.get_sndtimeo	= l2cap_sock_get_sndtimeo_cb,
 	.alloc_skb	= l2cap_sock_alloc_skb_cb,