Return-path: Received: from ist.d-labs.de ([213.239.218.44]:45940 "EHLO mx01.d-labs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932620Ab0JEKMp (ORCPT ); Tue, 5 Oct 2010 06:12:45 -0400 Date: Tue, 5 Oct 2010 12:12:42 +0200 From: Florian Mickler To: Stanislaw Gruszka Cc: stable@kernel.org, "linux-wireless@vger.kernel.org" , "Guy, Wey-Yi" , "Chatre, Reinette" , Intel Linux Wireless , "John W. Linville" , "Berg, Johannes" , "Cahill, Ben M" , "netdev@vger.kernel.org" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] iwl3945: queue the right work if the scan needs to be aborted Message-ID: <20101005121242.79cdafc2@schatten.dmk.lab> In-Reply-To: <20101005085717.GA18012@redhat.com> References: <20101005084305.52a31ed4@schatten.dmk.lab> <20101005085717.GA18012@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, 5 Oct 2010 10:57:17 +0200 Stanislaw Gruszka wrote: > On Tue, Oct 05, 2010 at 08:43:05AM +0200, Florian Mickler wrote: > > commit e7ee762cf074b0fd8eec483d0cef8fdbf0d04b81 > > > > > > Begin forwarded message: > > On Fri, 2010-09-24 at 09:22 -0700, Florian Mickler wrote: > > > iwl3945's scan_completed calls into the mac80211 stack which triggers a > > > warn on if there is no scan outstanding. > > > > > > This can be avoided by not calling scan_completed but abort_scan in > > > iwl3945_request_scan in the done: branch of the function which is used > > > as an error out. > > > > > > The done: branch seems to be an error-out branch, as, for example, if > > > iwl_is_ready(priv) returns false the done: branch is executed. > > > > > > NOTE: > > > I'm not familiar with the driver at all. > > > I just quickly scanned as a reaction to > > > > > > https://bugzilla.kernel.org/show_bug.cgi?id=17722 > > > > > > the users of scan_completed in the iwl3945 driver and noted the odd > > > discrepancy between the comment above this instance and the comment in > > > mac80211 scan_completed function. > > > Signed-off-by: Florian Mickler > > Acked-by: Wey-Yi Guy > > > --- > > go into wireless-2.6 and stable only, scan fix already in > > wireless-next-2.6 > > > > > Thanks > > Wey > > > > > drivers/net/wireless/iwlwifi/iwl-agn-lib.c | 2 +- > > > drivers/net/wireless/iwlwifi/iwl3945-base.c | 2 +- > > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c > > > index 9dd9e64..8fd00a6 100644 > > > --- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c > > > +++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c > > > @@ -1411,7 +1411,7 @@ void iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif) > > > clear_bit(STATUS_SCAN_HW, &priv->status); > > > clear_bit(STATUS_SCANNING, &priv->status); > > > /* inform mac80211 scan aborted */ > > > - queue_work(priv->workqueue, &priv->scan_completed); > > > + queue_work(priv->workqueue, &priv->abort_scan); > > Unfortunately this patch is not right thing to do. If you look at > abort_scan work, it do nothing if STATUS_SCAN_ABORTING bit is not set. > That's wrong because we have to complete scan (with abort == true). > If STATUS_SCAN_ABORTING will be set, abort_work will send scan cancel > commands to hardware what is wrong if scan was not started yet. > > What we can eventually do, except apply iwl-scan rewrite from > wireless-testing, is something like that: > > iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif) > > clear_bit(STATUS_SCAN_HW, &priv->status); > clear_bit(STATUS_SCANNING, &priv->status); > /* inform mac80211 scan aborted */ > set_bit(STATUS_SCAN_ABORTING, &priv->status); > queue_work(priv->workqueue, &priv->scan_completed); > > ieee80211_scan_completed > > if (!internal) { > bool aborted = test_bit(STATUS_SCAN_ABORTING, &priv->status); > ieee80211_scan_completed(priv->hw, aborted); > > } > > However, I do not think we should go with that to -stable (below > 2.6.36). IIRC warnings showed up in current 2.6.36-rc, because of > some other changes in the code. > > Stanislaw Thx for looking at this. I suspect you know the code better than I do.. what is about the first jump to :done in iwlagn_request_scan() if (!iwl_is_ready(priv)) { IWL_WARN(priv, "request scan called when driver not ready.\n"); goto done; } Does abort_scan need to do anything in that case? I can't see where we set up the hardware for scanning in that case. (I've gone through the codepath coming from the mac80211 hw_scan) Regards, Flo