[Bluetooth] Fix deadlock in the L2CAP layer

{

	struct sock *next = l2cap_pi(sk)->next_c, *prev = l2cap_pi(sk)->prev_c;

	write_lock(&l->lock);

	write_lock_bh(&l->lock);

	if (sk == l->head)

		l->head = next;

		l2cap_pi(next)->prev_c = prev;

	if (prev)

		l2cap_pi(prev)->next_c = next;

	write_unlock(&l->lock);

	write_unlock_bh(&l->lock);

	__sock_put(sk);

}

static inline void l2cap_chan_add(struct l2cap_conn *conn, struct sock *sk, struct sock *parent)

{

	struct l2cap_chan_list *l = &conn->chan_list;

	write_lock(&l->lock);

	write_lock_bh(&l->lock);

	__l2cap_chan_add(conn, sk, parent);

	write_unlock(&l->lock);

	write_unlock_bh(&l->lock);

}

static inline u8 l2cap_get_ident(struct l2cap_conn *conn)

	 *  200 - 254 are used by utilities like l2ping, etc.

	 */

	spin_lock(&conn->lock);

	spin_lock_bh(&conn->lock);

	if (++conn->tx_ident > 128)

		conn->tx_ident = 1;

	id = conn->tx_ident;

	spin_unlock(&conn->lock);

	spin_unlock_bh(&conn->lock);

	return id;

}

	if (!sk)

		goto response;

	write_lock(&list->lock);

	write_lock_bh(&list->lock);

	/* Check if we already have channel with that dcid */

	if (__l2cap_get_chan_by_dcid(list, scid)) {

		write_unlock(&list->lock);

		write_unlock_bh(&list->lock);

		sock_set_flag(sk, SOCK_ZAPPED);

		l2cap_sock_kill(sk);

		goto response;

	result = status = 0;

done:

	write_unlock(&list->lock);

	write_unlock_bh(&list->lock);

response:

	bh_unlock_sock(parent);