Bluetooth: Set P-bit for SREJ frame only if there are I-frames to ack
authorSzymon Janc <szymon.janc@tieto.com>
Wed, 11 Jan 2012 09:59:46 +0000 (10:59 +0100)
committerJohan Hedberg <johan.hedberg@intel.com>
Mon, 13 Feb 2012 15:01:25 +0000 (17:01 +0200)
commit0ef3ef0f676e3c7aaab4a936635f503770fd38b2
treee591de219bed8957eeb0a4dfafd0ee211370f42d
parent75b93b59ad625d734b1c7d7e05bf6b9898c8c28f
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>
net/bluetooth/l2cap_core.c