Bluetooth: Refactor l2cap_send_sframe

The new implementation uses struct l2cap_ctrl to set up the sframe
fields, and also reduces duplicate acks by canceling the ack timer
whenever an RR or RNR frame is sent.  sframe PDU generation is also
split in to a separate function to separate it from the logic related
to the connection state and sframe type.
Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

net/bluetooth/l2cap_core.c

@@ -848,15 +848,12 @@ static inline void __pack_control(struct l2cap_chan *chan,
 	}
 }
 
-static inline void l2cap_send_sframe(struct l2cap_chan *chan, u32 control)
+static struct sk_buff *l2cap_create_sframe_pdu(struct l2cap_chan *chan,
+					       u32 control)
 {
 	struct sk_buff *skb;
 	struct l2cap_hdr *lh;
-	struct l2cap_conn *conn = chan->conn;
-	int count, hlen;
-
-	if (chan->state != BT_CONNECTED)
-		return;
+	int hlen;
 
 	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
 		hlen = L2CAP_EXT_HDR_SIZE;
@@ -866,34 +863,64 @@ static inline void l2cap_send_sframe(struct l2cap_chan *chan, u32 control)
 	if (chan->fcs == L2CAP_FCS_CRC16)
 		hlen += L2CAP_FCS_SIZE;
 
-	BT_DBG("chan %p, control 0x%8.8x", chan, control);
-
-	count = min_t(unsigned int, conn->mtu, hlen);
+	skb = bt_skb_alloc(hlen, GFP_KERNEL);
 
-	control |= __set_sframe(chan);
-
-	if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
-		control |= __set_ctrl_final(chan);
-
-	if (test_and_clear_bit(CONN_SEND_PBIT, &chan->conn_state))
-		control |= __set_ctrl_poll(chan);
-
-	skb = bt_skb_alloc(count, GFP_ATOMIC);
 	if (!skb)
-		return;
+		return ERR_PTR(-ENOMEM);
 
 	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
 	lh->len = cpu_to_le16(hlen - L2CAP_HDR_SIZE);
 	lh->cid = cpu_to_le16(chan->dcid);
 
-	__put_control(chan, control, skb_put(skb, __ctrl_size(chan)));
+	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
+		put_unaligned_le32(control, skb_put(skb, L2CAP_EXT_CTRL_SIZE));
+	else
+		put_unaligned_le16(control, skb_put(skb, L2CAP_ENH_CTRL_SIZE));
 
 	if (chan->fcs == L2CAP_FCS_CRC16) {
-		u16 fcs = crc16(0, (u8 *)lh, count - L2CAP_FCS_SIZE);
+		u16 fcs = crc16(0, (u8 *)skb->data, skb->len);
 		put_unaligned_le16(fcs, skb_put(skb, L2CAP_FCS_SIZE));
 	}
 
 	skb->priority = HCI_PRIO_MAX;
+	return skb;
+}
+
+static void l2cap_send_sframe(struct l2cap_chan *chan,
+			      struct l2cap_ctrl *control)
+{
+	struct sk_buff *skb;
+	u32 control_field;
+
+	BT_DBG("chan %p, control %p", chan, control);
+
+	if (!control->sframe)
+		return;
+
+	if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state) &&
+	    !control->poll)
+		control->final = 1;
+
+	if (control->super == L2CAP_SUPER_RR)
+		clear_bit(CONN_RNR_SENT, &chan->conn_state);
+	else if (control->super == L2CAP_SUPER_RNR)
+		set_bit(CONN_RNR_SENT, &chan->conn_state);
+
+	if (control->super != L2CAP_SUPER_SREJ) {
+		chan->last_acked_seq = control->reqseq;
+		__clear_ack_timer(chan);
+	}
+
+	BT_DBG("reqseq %d, final %d, poll %d, super %d", control->reqseq,
+	       control->final, control->poll, control->super);
+
+	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
+		control_field = __pack_extended_control(control);
+	else
+		control_field = __pack_enhanced_control(control);
+
+	skb = l2cap_create_sframe_pdu(chan, control_field);
+	if (!IS_ERR(skb))
 		l2cap_do_send(chan, skb);
 }
 
@@ -906,8 +933,6 @@ static inline void l2cap_send_rr_or_rnr(struct l2cap_chan *chan, u32 control)
 		control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
 
 	control |= __set_reqseq(chan, chan->buffer_seq);
-
-	l2cap_send_sframe(chan, control);
 }
 
 static inline int __l2cap_no_conn_pending(struct l2cap_chan *chan)
@@ -1826,7 +1851,6 @@ static void __l2cap_send_ack(struct l2cap_chan *chan)
 	if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
 		control |= __set_ctrl_super(chan, L2CAP_SUPER_RNR);
 		set_bit(CONN_RNR_SENT, &chan->conn_state);
-		l2cap_send_sframe(chan, control);
 		return;
 	}
 
@@ -1834,7 +1858,6 @@ static void __l2cap_send_ack(struct l2cap_chan *chan)
 		return;
 
 	control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
-	l2cap_send_sframe(chan, control);
 }
 
 static void l2cap_send_ack(struct l2cap_chan *chan)
@@ -1853,8 +1876,6 @@ static void l2cap_send_srejtail(struct l2cap_chan *chan)
 
 	tail = list_entry((&chan->srej_l)->prev, struct srej_list, list);
 	control |= __set_reqseq(chan, tail->tx_seq);
-
-	l2cap_send_sframe(chan, control);
 }
 
 static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan,
@@ -2259,7 +2280,7 @@ static int l2cap_tx_state_xmit(struct l2cap_chan *chan,
 			local_control.super = L2CAP_SUPER_RR;
 			local_control.poll = 1;
 			local_control.reqseq = chan->buffer_seq;
-			l2cap_send_sframe(chan, 0);
+			l2cap_send_sframe(chan, &local_control);
 
 			chan->retry_count = 1;
 			__set_monitor_timer(chan);
@@ -2333,7 +2354,7 @@ static int l2cap_tx_state_wait_f(struct l2cap_chan *chan,
 			local_control.super = L2CAP_SUPER_RR;
 			local_control.poll = 1;
 			local_control.reqseq = chan->buffer_seq;
-			l2cap_send_sframe(chan, 0);
+			l2cap_send_sframe(chan, &local_control);
 
 			chan->retry_count = 1;
 			__set_monitor_timer(chan);
@@ -4233,7 +4254,6 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct l2cap_chan *chan)
 
 	if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
 		control |= __set_ctrl_super(chan, L2CAP_SUPER_RNR);
-		l2cap_send_sframe(chan, control);
 		set_bit(CONN_RNR_SENT, &chan->conn_state);
 	}
 
@@ -4245,7 +4265,6 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct l2cap_chan *chan)
 	if (!test_bit(CONN_LOCAL_BUSY, &chan->conn_state) &&
 			chan->frames_sent == 0) {
 		control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
-		l2cap_send_sframe(chan, control);
 	}
 }
 
@@ -4404,7 +4423,6 @@ static void l2cap_ertm_exit_local_busy(struct l2cap_chan *chan)
 	control = __set_reqseq(chan, chan->buffer_seq);
 	control |= __set_ctrl_poll(chan);
 	control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
-	l2cap_send_sframe(chan, control);
 	chan->retry_count = 1;
 
 	__clear_retrans_timer(chan);
@@ -4468,7 +4486,6 @@ static void l2cap_resend_srejframe(struct l2cap_chan *chan, u16 tx_seq)
 		}
 		control = __set_ctrl_super(chan, L2CAP_SUPER_SREJ);
 		control |= __set_reqseq(chan, l->tx_seq);
-		l2cap_send_sframe(chan, control);
 		list_del(&l->list);
 		list_add_tail(&l->list, &chan->srej_l);
 	}
@@ -4483,7 +4500,6 @@ static int l2cap_send_srejframe(struct l2cap_chan *chan, u16 tx_seq)
 		control = __set_ctrl_super(chan, L2CAP_SUPER_SREJ);
 		control |= __set_reqseq(chan, chan->expected_tx_seq);
 		l2cap_seq_list_append(&chan->srej_list, chan->expected_tx_seq);
-		l2cap_send_sframe(chan, control);
 
 		new = kzalloc(sizeof(struct srej_list), GFP_ATOMIC);
 		if (!new)
@@ -4767,7 +4783,6 @@ static inline void l2cap_data_channel_rnrframe(struct l2cap_chan *chan, u32 rx_c
 		l2cap_send_srejtail(chan);
 	} else {
 		rx_control = __set_ctrl_super(chan, L2CAP_SUPER_RR);
-		l2cap_send_sframe(chan, rx_control);
 	}
 }