From 86817a8e130f4fe6c60645bc104e9300d45367af Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Wed, 25 Apr 2012 16:36:12 -0700 Subject: [PATCH] Bluetooth: Improve ERTM sequence number offset calculation Instead of using modular division, the offset can be calculated using only addition and subtraction. The previous calculation did not work as intended and was more difficult to understand, involving unsigned integer underflow and a check for a negative value where one was not possible. Signed-off-by: Mat Martineau Acked-by: Marcel Holtmann Signed-off-by: Gustavo Padovan --- include/net/bluetooth/l2cap.h | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 22e9ec9885eb..92c042377bf0 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -724,13 +724,10 @@ static inline bool l2cap_clear_timer(struct l2cap_chan *chan, static inline int __seq_offset(struct l2cap_chan *chan, __u16 seq1, __u16 seq2) { - int offset; - - offset = (seq1 - seq2) % (chan->tx_win_max + 1); - if (offset < 0) - offset += (chan->tx_win_max + 1); - - return offset; + if (seq1 >= seq2) + return seq1 - seq2; + else + return chan->tx_win_max + 1 - seq2 + seq1; } static inline __u16 __next_seq(struct l2cap_chan *chan, __u16 seq) -- 2.39.5