From: "Guy, Wey-Yi" <wey-yi.w.guy@intel.com>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>,
"Chatre, Reinette" <reinette.chatre@intel.com>,
"John W. Linville" <linville@tuxdriver.com>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 0/13] iwlwifi: rewrite iwl-scan.c to avoid race conditions
Date: Fri, 03 Sep 2010 08:04:53 -0700 [thread overview]
Message-ID: <1283526293.5211.18.camel@wwguy-ubuntu> (raw)
In-Reply-To: <1283515056-11523-1-git-send-email-sgruszka@redhat.com>
Hi Gruszka,
On Fri, 2010-09-03 at 04:57 -0700, Stanislaw Gruszka wrote:
> Avoid iwlwifi hardware scanning race conditions
> that may lead to not call ieee80211_scan_completed() (what in
> consequences gives "WARNING: at net/wireless/core.c:614
> wdev_cleanup_work+0xb7/0xf0"), or call iee80211_scan_completed() more
> then once (what gives " WARNING: at net/mac80211/scan.c:312
> ieee80211_scan_completed+0x5f/0x1f1").
>
> First problem (warning in wdev_cleanup_work) make any further scan
> request from cfg80211 are ignored by mac80211 with EBUSY error,
> hence NetworkManager can not perform successful scan and not allow
> to establish a new connection. So after suspend/resume (but maybe
> not only then) user is not able to connect to wireless network again.
>
> We can not rely on that the commands (start and abort scan) are
> successful. Even if they are successfully send to the hardware, we can
> not get back notification from firmware (i.e. firmware hung or was
> reseted), or we can get notification when we actually perform abort
> scan in driver code or after that.
>
> To assure we call ieee80211_scan_completed() only once when scan
> was started we use SCAN_SCANNING bit. Code path, which first clear
> STATUS_SCANNING bit will call ieee80211_scan_completed().
> We do this in many cases, in scan complete notification, scan
> abort, device down, etc. Each time we check SCANNING bit.
>
A lot of changes, great jobs. How much test you done for different
devices? Scan is a very important function and I am also not expert in
this area.
Thanks
Wey
next prev parent reply other threads:[~2010-09-03 15:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-03 11:57 [PATCH 0/13] iwlwifi: rewrite iwl-scan.c to avoid race conditions Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 01/13] iwlwifi: remove unused conf variables Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 02/13] iwlwifi: unify scan start checks Stanislaw Gruszka
2010-09-03 14:23 ` Guy, Wey-Yi
2010-09-03 14:25 ` Berg, Johannes
2010-09-06 7:30 ` Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 03/13] iwlwifi: move scan completed flags handling Stanislaw Gruszka
2010-09-03 14:29 ` Guy, Wey-Yi
2010-09-03 14:31 ` Berg, Johannes
2010-09-03 11:57 ` [PATCH 04/13] iwlwifi: cancel scan when down the device Stanislaw Gruszka
2010-09-03 12:07 ` Johannes Berg
2010-09-03 14:38 ` Guy, Wey-Yi
2010-09-06 7:32 ` Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 05/13] iwlwifi: use IWL_DEBUG_SCAN Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 06/13] iwlwifi: report scan completion when abort fail Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 07/13] iwlwifi: do not queue abort_scan work if can sleep Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 08/13] iwlwifi: avoid dropping muttex in iwl_scan_cancel_timeout Stanislaw Gruszka
2010-09-03 14:53 ` Guy, Wey-Yi
2010-09-06 7:33 ` Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 09/13] iwlwifi: rewrite scan completion Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 10/13] iwlwifi: force scan complete after timeout Stanislaw Gruszka
2010-09-03 12:15 ` Johannes Berg
2010-09-03 11:57 ` [PATCH 11/13] iwlwifi: assure we complete scan in scan_abort and scan_check works Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 12/13] iwlwifi: do not force complete scan too early Stanislaw Gruszka
2010-09-03 11:57 ` [PATCH 13/13] mac80211: wait for scan work complete before restarting hw Stanislaw Gruszka
2010-09-03 12:21 ` [PATCH 0/13] iwlwifi: rewrite iwl-scan.c to avoid race conditions Johannes Berg
2010-09-03 12:55 ` Stanislaw Gruszka
2010-09-03 13:11 ` Johannes Berg
2010-09-03 15:04 ` Guy, Wey-Yi [this message]
2010-09-06 7:37 ` Stanislaw Gruszka
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=1283526293.5211.18.camel@wwguy-ubuntu \
--to=wey-yi.w.guy@intel.com \
--cc=johannes@sipsolutions.net \
--cc=linux-wireless@vger.kernel.org \
--cc=linville@tuxdriver.com \
--cc=reinette.chatre@intel.com \
--cc=sgruszka@redhat.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).