Hi Mat,
* Mat Martineau <mathewm@xxxxxxxxxxxxxx> [2012-04-27 16:50:53 -0700]:
> The ERTM and streaming mode transmit queue must only be accessed while
> the L2CAP channel lock is held. Locking the channel before calling
> l2cap_chan_send ensures that multiple threads cannot simultaneously
> manipulate the queue when sending and receiving concurrently.
>
> L2CAP channel locking had previously moved to the l2cap_chan struct
> instead of the associated socket, so some of the old socket locking
> can also be removed in this patch.
>
> Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
> ---
> include/net/bluetooth/bluetooth.h | 2 --
> net/bluetooth/l2cap_sock.c | 15 ++++++++-------
> 2 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> index 2fb268f..90678a9 100644
> --- a/include/net/bluetooth/bluetooth.h
> +++ b/include/net/bluetooth/bluetooth.h
> @@ -256,12 +256,10 @@ static inline struct sk_buff *bt_skb_send_alloc(struct sock *sk,
> {
> struct sk_buff *skb;
>
> - release_sock(sk);
> if ((skb = sock_alloc_send_skb(sk, len + BT_SKB_RESERVE, nb, err))) {
> skb_reserve(skb, BT_SKB_RESERVE);
> bt_cb(skb)->incoming = 0;
> }
> - lock_sock(sk);
>
> if (!skb && *err)
> return NULL;
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 82b6368..ac8ce10 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -716,16 +716,13 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
> if (msg->msg_flags & MSG_OOB)
> return -EOPNOTSUPP;
>
> - lock_sock(sk);
> -
> - if (sk->sk_state != BT_CONNECTED) {
> - release_sock(sk);
> + if (sk->sk_state != BT_CONNECTED)
> return -ENOTCONN;
> - }
>
> + l2cap_chan_lock(chan);
> err = l2cap_chan_send(chan, msg, len, sk->sk_priority);
> + l2cap_chan_unlock(chan);
I would move these l2cap_chan_{,un}lock calls to inside
l2cap_chan_send(). The less we use l2cap_chan_* functions here the
better.
>
> - release_sock(sk);
> return err;
> }
>
> @@ -936,9 +933,13 @@ static struct sk_buff *l2cap_sock_alloc_skb_cb(struct l2cap_chan *chan,
> struct sk_buff *skb;
> int err;
>
> + l2cap_chan_unlock(chan);
> +
> skb = bt_skb_send_alloc(chan->sk, len, nb, &err);
> if (!skb)
> - return (ERR_PTR(err));
> + skb = ERR_PTR(err);
> +
> + l2cap_chan_lock(chan);
I would suggest the same here, but it might not be worth, since we would
need to create wrapper to call alloc_skb().
Gustavo
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