Bluetooth: Add timer to Acknowledge I-frames

We ack I-frames on each txWindow/5 I-frames received, but if the sender
stop to send I-frames and it's not a txWindow multiple we can leave some
frames unacked.
So I added a timer to ack I-frames on this case. The timer expires in
200ms.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index d9c20c3d6f3d..48f10f46c73d 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -35,6 +35,7 @@
 #define L2CAP_DEFAULT_RETRANS_TO        1000    /* 1 second */
 #define L2CAP_DEFAULT_MONITOR_TO        12000   /* 12 seconds */
 #define L2CAP_DEFAULT_MAX_PDU_SIZE      672
+#define L2CAP_DEFAULT_ACK_TO            200
 
 #define L2CAP_CONN_TIMEOUT      (40000) /* 40 seconds */
 #define L2CAP_INFO_TIMEOUT      (4000)  /*  4 seconds */
@@ -348,6 +349,7 @@ struct l2cap_pinfo {
 
         struct timer_list       retrans_timer;
         struct timer_list       monitor_timer;
+        struct timer_list       ack_timer;
         struct sk_buff_head     tx_queue;
         struct sk_buff_head     srej_queue;
         struct srej_list        srej_l;
@@ -382,6 +384,8 @@ struct l2cap_pinfo {
                 jiffies +  msecs_to_jiffies(L2CAP_DEFAULT_RETRANS_TO));
 #define __mod_monitor_timer() mod_timer(&l2cap_pi(sk)->monitor_timer, \
                 jiffies + msecs_to_jiffies(L2CAP_DEFAULT_MONITOR_TO));
+#define __mod_ack_timer() mod_timer(&l2cap_pi(sk)->ack_timer, \
+                jiffies + msecs_to_jiffies(L2CAP_DEFAULT_ACK_TO));
 
 static inline int l2cap_tx_window_full(struct sock *sk)
 {
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index f3869857ee9f..03006568f8a1 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -2235,6 +2235,15 @@ static void l2cap_add_conf_opt(void **ptr, u8 type, u8 len, unsigned long val)
         *ptr += L2CAP_CONF_OPT_SIZE + len;
 }
 
+static void l2cap_ack_timeout(unsigned long arg)
+{
+        struct sock *sk = (void *) arg;
+
+        bh_lock_sock(sk);
+        l2cap_send_ack(l2cap_pi(sk));
+        bh_unlock_sock(sk);
+}
+
 static inline void l2cap_ertm_init(struct sock *sk)
 {
         l2cap_pi(sk)->expected_ack_seq = 0;
@@ -2247,6 +2256,8 @@ static inline void l2cap_ertm_init(struct sock *sk)
                         l2cap_retrans_timeout, (unsigned long) sk);
         setup_timer(&l2cap_pi(sk)->monitor_timer,
                         l2cap_monitor_timeout, (unsigned long) sk);
+        setup_timer(&l2cap_pi(sk)->ack_timer,
+                        l2cap_ack_timeout, (unsigned long) sk);
 
         __skb_queue_head_init(SREJ_QUEUE(sk));
 }
@@ -2975,6 +2986,7 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
                 skb_queue_purge(SREJ_QUEUE(sk));
                 del_timer(&l2cap_pi(sk)->retrans_timer);
                 del_timer(&l2cap_pi(sk)->monitor_timer);
+                del_timer(&l2cap_pi(sk)->ack_timer);
         }
 
         l2cap_chan_del(sk, ECONNRESET);
@@ -3005,6 +3017,7 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd
                 skb_queue_purge(SREJ_QUEUE(sk));
                 del_timer(&l2cap_pi(sk)->retrans_timer);
                 del_timer(&l2cap_pi(sk)->monitor_timer);
+                del_timer(&l2cap_pi(sk)->ack_timer);
         }
 
         l2cap_chan_del(sk, 0);
@@ -3484,6 +3497,8 @@ expected:
         if (err < 0)
                 return err;
 
+        __mod_ack_timer();
+
         pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
         if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1)
                 l2cap_send_ack(pi);