Linux wireless drivers development
 help / color / mirror / Atom feed
From: Pavel Roskin <proski@gnu.org>
To: Dan Halperin <dhalperi@cs.washington.edu>,
	linux-wireless@vger.kernel.org,
	"John W. Linville" <linville@tuxdriver.com>
Subject: [PATCH] rc80211_minstrel: fix contention window calculation
Date: Tue, 15 Sep 2009 22:24:30 -0400	[thread overview]
Message-ID: <20090916022430.27557.93510.stgit@mj.roinet.com> (raw)

The contention window is supposed to be a power of two minus one, i.e.
15, 31, 63, 127...  minstrel_rate_init() forgets to subtract 1, so the
sequence becomes 15, 32, 66, 134...

Bug reported by Dan Halperin <dhalperi@cs.washington.edu>

Signed-off-by: Pavel Roskin <proski@gnu.org>
---
 net/mac80211/rc80211_minstrel.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index 7c51429..6e5d68b 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -418,7 +418,7 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
 
 			/* contention window */
 			tx_time_single += t_slot + min(cw, mp->cw_max);
-			cw = (cw + 1) << 1;
+			cw = (cw << 1) | 1;
 
 			tx_time += tx_time_single;
 			tx_time_cts += tx_time_single + mi->sp_ack_dur;

                 reply	other threads:[~2009-09-16  2:24 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20090916022430.27557.93510.stgit@mj.roinet.com \
    --to=proski@gnu.org \
    --cc=dhalperi@cs.washington.edu \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linville@tuxdriver.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox