Bluetooth: Remove L2CAP busy queue

The ERTM receive buffer is now handled in a way that does not require
the busy queue and the associated polling code.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

2 files changed, 8 insertions, 121 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 66b8d9688d9e..578545a2a492 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -37,7 +37,6 @@
 #define L2CAP_DEFAULT_MONITOR_TO        12000   /* 12 seconds */
 #define L2CAP_DEFAULT_MAX_PDU_SIZE      1009    /* Sized for 3-DH5 packet */
 #define L2CAP_DEFAULT_ACK_TO            200
-#define L2CAP_LOCAL_BUSY_TRIES          12
 #define L2CAP_LE_DEFAULT_MTU            23
 
 #define L2CAP_CONN_TIMEOUT      (40000) /* 40 seconds */
@@ -352,8 +351,6 @@ struct l2cap_chan {
         struct sk_buff          *tx_send_head;
         struct sk_buff_head     tx_q;
         struct sk_buff_head     srej_q;
-        struct sk_buff_head     busy_q;
-        struct work_struct      busy_work;
         struct list_head        srej_l;
 
         struct list_head list;
@@ -450,7 +447,6 @@ enum {
         CONN_REJ_ACT,
         CONN_SEND_FBIT,
         CONN_RNR_SENT,
-        CONN_SAR_RETRY,
 };
 
 #define __set_chan_timer(c, t) l2cap_set_timer(c, &c->chan_timer, (t))
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ea9c7d061046..2c5d335bde87 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -61,13 +61,9 @@ int disable_ertm;
 static u32 l2cap_feat_mask = L2CAP_FEAT_FIXED_CHAN;
 static u8 l2cap_fixed_chan[8] = { 0x02, };
 
-static struct workqueue_struct *_busy_wq;
-
 static LIST_HEAD(chan_list);
 static DEFINE_RWLOCK(chan_list_lock);
 
-static void l2cap_busy_work(struct work_struct *work);
-
 static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
                                 u8 code, u8 ident, u16 dlen, void *data);
 static void l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len,
@@ -395,7 +391,6 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
                 __clear_ack_timer(chan);
 
                 skb_queue_purge(&chan->srej_q);
-                skb_queue_purge(&chan->busy_q);
 
                 list_for_each_entry_safe(l, tmp, &chan->srej_l, list) {
                         list_del(&l->list);
@@ -1873,11 +1868,9 @@ static inline void l2cap_ertm_init(struct l2cap_chan *chan)
         setup_timer(&chan->ack_timer, l2cap_ack_timeout, (unsigned long) chan);
 
         skb_queue_head_init(&chan->srej_q);
-        skb_queue_head_init(&chan->busy_q);
 
         INIT_LIST_HEAD(&chan->srej_l);
 
-        INIT_WORK(&chan->busy_work, l2cap_busy_work);
 
         sk->sk_backlog_rcv = l2cap_ertm_data_rcv;
 }
@@ -3182,32 +3175,27 @@ static int l2cap_ertm_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *sk
                 if (!chan->sdu)
                         goto disconnect;
 
-                if (!test_bit(CONN_SAR_RETRY, &chan->conn_state)) {
-                        chan->partial_sdu_len += skb->len;
+                chan->partial_sdu_len += skb->len;
 
-                        if (chan->partial_sdu_len > chan->imtu)
-                                goto drop;
+                if (chan->partial_sdu_len > chan->imtu)
+                        goto drop;
 
-                        if (chan->partial_sdu_len != chan->sdu_len)
-                                goto drop;
+                if (chan->partial_sdu_len != chan->sdu_len)
+                        goto drop;
 
-                        memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
-                }
+                memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
 
                 _skb = skb_clone(chan->sdu, GFP_ATOMIC);
                 if (!_skb) {
-                        set_bit(CONN_SAR_RETRY, &chan->conn_state);
                         return -ENOMEM;
                 }
 
                 err = chan->ops->recv(chan->data, _skb);
                 if (err < 0) {
                         kfree_skb(_skb);
-                        set_bit(CONN_SAR_RETRY, &chan->conn_state);
                         return err;
                 }
 
-                clear_bit(CONN_SAR_RETRY, &chan->conn_state);
                 clear_bit(CONN_SAR_SDU, &chan->conn_state);
 
                 kfree_skb(chan->sdu);
@@ -3268,93 +3256,6 @@ done:
         BT_DBG("chan %p, Exit local busy", chan);
 }
 
-static int l2cap_try_push_rx_skb(struct l2cap_chan *chan)
-{
-        struct sk_buff *skb;
-        u16 control;
-        int err;
-
-        while ((skb = skb_dequeue(&chan->busy_q))) {
-                control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
-                err = l2cap_ertm_reassembly_sdu(chan, skb, control);
-                if (err < 0) {
-                        skb_queue_head(&chan->busy_q, skb);
-                        return -EBUSY;
-                }
-
-                chan->buffer_seq = (chan->buffer_seq + 1) % 64;
-        }
-
-        l2cap_ertm_exit_local_busy(chan);
-
-        return 0;
-}
-
-static void l2cap_busy_work(struct work_struct *work)
-{
-        DECLARE_WAITQUEUE(wait, current);
-        struct l2cap_chan *chan =
-                container_of(work, struct l2cap_chan, busy_work);
-        struct sock *sk = chan->sk;
-        int n_tries = 0, timeo = HZ/5, err;
-        struct sk_buff *skb;
-
-        lock_sock(sk);
-
-        add_wait_queue(sk_sleep(sk), &wait);
-        while ((skb = skb_peek(&chan->busy_q))) {
-                set_current_state(TASK_INTERRUPTIBLE);
-
-                if (n_tries++ > L2CAP_LOCAL_BUSY_TRIES) {
-                        err = -EBUSY;
-                        l2cap_send_disconn_req(chan->conn, chan, EBUSY);
-                        break;
-                }
-
-                if (!timeo)
-                        timeo = HZ/5;
-
-                if (signal_pending(current)) {
-                        err = sock_intr_errno(timeo);
-                        break;
-                }
-
-                release_sock(sk);
-                timeo = schedule_timeout(timeo);
-                lock_sock(sk);
-
-                err = sock_error(sk);
-                if (err)
-                        break;
-
-                if (l2cap_try_push_rx_skb(chan) == 0)
-                        break;
-        }
-
-        set_current_state(TASK_RUNNING);
-        remove_wait_queue(sk_sleep(sk), &wait);
-
-        release_sock(sk);
-}
-
-static int l2cap_push_rx_skb(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
-{
-        int err;
-
-        if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
-                bt_cb(skb)->sar = control >> L2CAP_CTRL_SAR_SHIFT;
-                __skb_queue_tail(&chan->busy_q, skb);
-                return l2cap_try_push_rx_skb(chan);
-
-
-        }
-
-        err = l2cap_ertm_reassembly_sdu(chan, skb, control);
-        chan->buffer_seq = (chan->buffer_seq + 1) % 64;
-
-        return err;
-}
-
 void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
 {
         if (chan->mode == L2CAP_MODE_ERTM) {
@@ -3612,7 +3513,6 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u16 rx_cont
                 chan->buffer_seq_srej = chan->buffer_seq;
 
                 __skb_queue_head_init(&chan->srej_q);
-                __skb_queue_head_init(&chan->busy_q);
                 l2cap_add_to_srej_queue(chan, skb, tx_seq, sar);
 
                 set_bit(CONN_SEND_PBIT, &chan->conn_state);
@@ -3633,7 +3533,8 @@ expected:
                 return 0;
         }
 
-        err = l2cap_push_rx_skb(chan, skb, rx_control);
+        err = l2cap_ertm_reassembly_sdu(chan, skb, rx_control);
+        chan->buffer_seq = (chan->buffer_seq + 1) % 64;
         if (err < 0) {
                 l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
                 return err;
@@ -4439,12 +4340,6 @@ int __init l2cap_init(void)
         if (err < 0)
                 return err;
 
-        _busy_wq = create_singlethread_workqueue("l2cap");
-        if (!_busy_wq) {
-                err = -ENOMEM;
-                goto error;
-        }
-
         err = hci_register_proto(&l2cap_hci_proto);
         if (err < 0) {
                 BT_ERR("L2CAP protocol registration failed");
@@ -4462,7 +4357,6 @@ int __init l2cap_init(void)
         return 0;
 
 error:
-        destroy_workqueue(_busy_wq);
         l2cap_cleanup_sockets();
         return err;
 }
@@ -4471,9 +4365,6 @@ void l2cap_exit(void)
 {
         debugfs_remove(l2cap_debugfs);
 
-        flush_workqueue(_busy_wq);
-        destroy_workqueue(_busy_wq);
-
         if (hci_unregister_proto(&l2cap_hci_proto) < 0)
                 BT_ERR("L2CAP protocol unregistration failed");