Bluetooth: Make __l2cap_wait_ack more efficient

Use chan->state instead of chan->conn because waiting
for ACK's is only possible in the BT_CONNECTED state.
Also avoids reference to the conn structure so makes
locking easier.

Only call __l2cap_wait_ack() when the needed condition
of chan->unacked_frames > 0 && chan->state == BT_CONNECTED
is true and convert the while loop to a do while loop.

__l2cap_wait_ack() change the function prototype to
pass in the chan variable as chan is already available
in the calling function l2cap_sock_shutdown(). Avoids
locking issues.

Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 3794c2386c211c7ba934367f5ecc95c1342c87f7..29042880c449d24d8fd5d18fceb4387f0835aafa 100644 (file)
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1054,16 +1054,15 @@ static void l2cap_sock_kill(struct sock *sk)
        sock_put(sk);
 }
 
-static int __l2cap_wait_ack(struct sock *sk)
+static int __l2cap_wait_ack(struct sock *sk, struct l2cap_chan *chan)
 {
-       struct l2cap_chan *chan = l2cap_pi(sk)->chan;
        DECLARE_WAITQUEUE(wait, current);
        int err = 0;
        int timeo = HZ/5;
 
        add_wait_queue(sk_sleep(sk), &wait);
        set_current_state(TASK_INTERRUPTIBLE);
-       while (chan->unacked_frames > 0 && chan->conn) {
+       do {
                if (!timeo)
                        timeo = HZ/5;
 
@@ -1080,7 +1079,10 @@ static int __l2cap_wait_ack(struct sock *sk)
                err = sock_error(sk);
                if (err)
                        break;
-       }
+
+       } while (chan->unacked_frames > 0 &&
+                chan->state == BT_CONNECTED);
+
        set_current_state(TASK_RUNNING);
        remove_wait_queue(sk_sleep(sk), &wait);
        return err;
@@ -1115,8 +1117,10 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
        lock_sock(sk);
 
        if (!sk->sk_shutdown) {
-               if (chan->mode == L2CAP_MODE_ERTM)
-                       err = __l2cap_wait_ack(sk);
+               if (chan->mode == L2CAP_MODE_ERTM &&
+                   chan->unacked_frames > 0 &&
+                   chan->state == BT_CONNECTED)
+                       err = __l2cap_wait_ack(sk, chan);
 
                sk->sk_shutdown = SHUTDOWN_MASK;