From: Christian Lamparter <chunkeey@googlemail.com>
To: "linux-wireless" <linux-wireless@vger.kernel.org>
Cc: "John W. Linville" <linville@tuxdriver.com>,
Johannes Berg <johannes@sipsolutions.net>
Subject: [PATCH] mac80211: temporarily disable reorder release timer
Date: Fri, 8 Oct 2010 21:51:26 +0200 [thread overview]
Message-ID: <201010082151.27177.chunkeey@googlemail.com> (raw)
Serve threading problems with the current release
reorder timer implementation have been discovered.
A lengthy discussion which lists some of the pitfalls
and possible solutions can be found at:
http://marc.info/?t=128635927000001
But Due to the complicated nature of the subject and
the foreseeable advent of a new -rc1 cycle, it was
decided to disable the feature for the time being.
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
---
if we want, we could add a WARN_ON into the timer too.
---
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b67221d..e1e02b5 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -622,6 +622,26 @@ static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
tid_agg_rx->buf_size;
}
+ /*
+ * Disable the reorder release timer for now.
+ *
+ * The current implementation lacks a proper locking scheme
+ * which would protect vital statistic and debug counters
+ * from being updated by two different, but concurrent BHs.
+ *
+ * more information about the topic is available from:
+ * - thread: http://marc.info/?t=128635927000001
+ *
+ * Why did it break:
+ * => http://marc.info/?l=linux-wireless&m=128636170811964
+ * "Basically the thing is that until your patch, the data
+ * in the struct didn't actually need locking because it
+ * was accessed by the RX path only which is not concurrent."
+ *
+ * List of known things that need to be fixed/considered:
+ * => http://marc.info/?l=linux-wireless&m=128656352920957
+ *
+
if (tid_agg_rx->stored_mpdu_num) {
j = index = seq_sub(tid_agg_rx->head_seq_num,
tid_agg_rx->ssn) % tid_agg_rx->buf_size;
@@ -640,6 +660,9 @@ static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
} else {
del_timer(&tid_agg_rx->reorder_timer);
}
+ */
+
+set_release_timer:
}
/*
reply other threads:[~2010-10-08 19:51 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=201010082151.27177.chunkeey@googlemail.com \
--to=chunkeey@googlemail.com \
--cc=johannes@sipsolutions.net \
--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;
as well as URLs for NNTP newsgroup(s).