Bluetooth: Set P-bit for SREJ frame only if there are I-frames to ack

SREJ frame with P-bit set acknowledges I-frames numbered up to
(ReqSeq - 1). With this patch P-bit in SREJ is set only when there are
some I-frames to ack.

This fixes ambiguous situation when lost of I-frame with TxSeq=0 would
result in sending SREJ acking all previous I-frames.
Consider following scenario:
TxWindow=3

HostA: sent I-frame TxSeq=0
HostA: sent I-frame TxSeq=1
HostA: sent I-frame TxSeq=2
HostB: missed I-frame TxSeq=0
HostB: received I-frame TxSeq=1
HostB: sent SREJ ReqSeq=0 Pbit=1
HostA: received SREJ ReqSeq=0 Pbit=1   <- All I-frames acked or not?
...

Signed-off-by: Szymon Janc <szymon.janc@tieto.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This commit is contained in:
Szymon Janc 2012-01-11 10:59:46 +01:00 committed by Johan Hedberg
parent 75b93b59ad
commit 0ef3ef0f67

View File

@ -3927,15 +3927,15 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
__skb_queue_head_init(&chan->srej_q);
l2cap_add_to_srej_queue(chan, skb, tx_seq, sar);
set_bit(CONN_SEND_PBIT, &chan->conn_state);
/* Set P-bit only if there are some I-frames to ack. */
if (__clear_ack_timer(chan))
set_bit(CONN_SEND_PBIT, &chan->conn_state);
err = l2cap_send_srejframe(chan, tx_seq);
if (err < 0) {
l2cap_send_disconn_req(chan->conn, chan, -err);
return err;
}
__clear_ack_timer(chan);
}
return 0;