netdev - [PATCH 57/64] Bluetooth: Fix spec error in the RemoteBusy Logic

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Message-Id: <844c0972427ee5f661158160aaca10b22b3dda60.1273484098.git.marcel@holtmann.org>
Date:	Mon, 10 May 2010 11:37:47 +0200
From:	Marcel Holtmann <marcel@...tmann.org>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: [PATCH 57/64] Bluetooth: Fix spec error in the RemoteBusy Logic

From: Gustavo F. Padovan <padovan@...fusion.mobi>

On the receipt of an RR(P=1) under RemoteBusy set to TRUE(on the RECV
state table) we have to call sendIorRRorRNR(F=1) and just after set
RemoteBusy to False. This leads to a freeze in the sending process since
it's not allowed send data with RemoteBusy set to true and no one
call SendPending-I-Frames after set RemoteBusy to false(The last action
for that event).

Actually sendIorRRorRNR() calls SendPending-I-Frames but at that moment
RemoteBusy is still True and we cannot send any frame, after, no one
calls SendPending-I-Frames again and the sending process stops.

The solution here is to set RemoteBusy to false inside
SendPending-I-Frames just before call SendPending-I-Frames. That will
make SendPending-I-Frames able to send frames. This solution is similar
to what RR(P=0)(F=0) on the RECV table and RR(P=1) on the SREJ_SENT
table do.

Actually doesn't make any sense call SendPending-I-Frames if we can send
any frame, i. e., RemoteBusy is True.

Signed-off-by: Gustavo F. Padovan <padovan@...fusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
---
 net/bluetooth/l2cap.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 9ef01c3..ba49f9a 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3379,6 +3379,8 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct sock *sk)
 	if (pi->conn_state & L2CAP_CONN_REMOTE_BUSY && pi->unacked_frames > 0)
 		__mod_retrans_timer();

+	pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;
+
 	spin_lock_bh(&pi->send_lock);
 	l2cap_ertm_send(sk);
 	spin_unlock_bh(&pi->send_lock);
@@ -3936,7 +3938,6 @@ static inline void l2cap_data_channel_rrframe(struct sock *sk, u16 rx_control)
 			l2cap_send_srejtail(sk);
 		} else {
 			l2cap_send_i_or_rr_or_rnr(sk);
-			pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;
 		}

 	} else if (rx_control & L2CAP_CTRL_FINAL) {
-- 
1.6.6.1

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