Bluetooth: Remove the send_lock spinlock from ERTM

Using a lock to deal with the ERTM race condition - interruption with
new data from the hci layer - is wrong. We should use the native skb
backlog queue.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index f8bae54..7df70e4 100644 (file)
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -358,7 +358,6 @@ struct l2cap_pinfo {
 
        __le16          sport;
 
-       spinlock_t              send_lock;
        struct timer_list       retrans_timer;
        struct timer_list       monitor_timer;
        struct timer_list       ack_timer;

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index f6e46fd..dc8601f 100644 (file)
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1562,16 +1562,11 @@ static int l2cap_retransmit_frames(struct sock *sk)
        struct l2cap_pinfo *pi = l2cap_pi(sk);
        int ret;
 
-       spin_lock_bh(&pi->send_lock);
-
        if (!skb_queue_empty(TX_QUEUE(sk)))
                sk->sk_send_head = TX_QUEUE(sk)->next;
 
        pi->next_tx_seq = pi->expected_ack_seq;
        ret = l2cap_ertm_send(sk);
-
-       spin_unlock_bh(&pi->send_lock);
-
        return ret;
 }
 
@@ -1579,7 +1574,6 @@ static void l2cap_send_ack(struct l2cap_pinfo *pi)
 {
        struct sock *sk = (struct sock *)pi;
        u16 control = 0;
-       int nframes;
 
        control |= pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT;
 
@@ -1590,11 +1584,7 @@ static void l2cap_send_ack(struct l2cap_pinfo *pi)
                return;
        }
 
-       spin_lock_bh(&pi->send_lock);
-       nframes = l2cap_ertm_send(sk);
-       spin_unlock_bh(&pi->send_lock);
-
-       if (nframes > 0)
+       if (l2cap_ertm_send(sk) > 0)
                return;
 
        control |= L2CAP_SUPER_RCV_READY;
@@ -1789,10 +1779,8 @@ static inline int l2cap_sar_segment_sdu(struct sock *sk, struct msghdr *msg, siz
                size += buflen;
        }
        skb_queue_splice_tail(&sar_queue, TX_QUEUE(sk));
-       spin_lock_bh(&pi->send_lock);
        if (sk->sk_send_head == NULL)
                sk->sk_send_head = sar_queue.next;
-       spin_unlock_bh(&pi->send_lock);
 
        return size;
 }
@@ -1864,14 +1852,9 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
                        }
                        __skb_queue_tail(TX_QUEUE(sk), skb);
 
-                       if (pi->mode == L2CAP_MODE_ERTM)
-                               spin_lock_bh(&pi->send_lock);
-
                        if (sk->sk_send_head == NULL)
                                sk->sk_send_head = skb;
 
-                       if (pi->mode == L2CAP_MODE_ERTM)
-                               spin_unlock_bh(&pi->send_lock);
                } else {
                /* Segment SDU into multiples PDUs */
                        err = l2cap_sar_segment_sdu(sk, msg, len);
@@ -1887,9 +1870,7 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
                                err = len;
                                break;
                        }
-                       spin_lock_bh(&pi->send_lock);
                        err = l2cap_ertm_send(sk);
-                       spin_unlock_bh(&pi->send_lock);
                }
 
                if (err >= 0)
@@ -2464,7 +2445,6 @@ static inline void l2cap_ertm_init(struct sock *sk)
 
        __skb_queue_head_init(SREJ_QUEUE(sk));
        __skb_queue_head_init(BUSY_QUEUE(sk));
-       spin_lock_init(&l2cap_pi(sk)->send_lock);
 
        INIT_WORK(&l2cap_pi(sk)->busy_work, l2cap_busy_work);
 }
@@ -3462,9 +3442,7 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct sock *sk)
        if (pi->conn_state & L2CAP_CONN_REMOTE_BUSY)
                l2cap_retransmit_frames(sk);
 
-       spin_lock_bh(&pi->send_lock);
        l2cap_ertm_send(sk);
-       spin_unlock_bh(&pi->send_lock);
 
        if (!(pi->conn_state & L2CAP_CONN_LOCAL_BUSY) &&
                        pi->frames_sent == 0) {
@@ -4066,9 +4044,7 @@ static inline void l2cap_data_channel_rrframe(struct sock *sk, u16 rx_control)
                if (pi->conn_state & L2CAP_CONN_SREJ_SENT) {
                        l2cap_send_ack(pi);
                } else {
-                       spin_lock_bh(&pi->send_lock);
                        l2cap_ertm_send(sk);
-                       spin_unlock_bh(&pi->send_lock);
                }
        }
 }
@@ -4113,9 +4089,7 @@ static inline void l2cap_data_channel_srejframe(struct sock *sk, u16 rx_control)
                pi->conn_state |= L2CAP_CONN_SEND_FBIT;
                l2cap_retransmit_one_frame(sk, tx_seq);
 
-               spin_lock_bh(&pi->send_lock);
                l2cap_ertm_send(sk);
-               spin_unlock_bh(&pi->send_lock);
 
                if (pi->conn_state & L2CAP_CONN_WAIT_F) {
                        pi->srej_save_reqseq = tx_seq;