Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:56749 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752806Ab0DIHoV (ORCPT ); Fri, 9 Apr 2010 03:44:21 -0400 Subject: Re: [PATCH] mac80211: Prevent starting of hw scan if it is already in progress From: Johannes Berg To: Teemu Paasikivi Cc: linville@tuxdriver.com, linux-wireless@vger.kernel.org, "Luis R. Rodriguez" In-Reply-To: <1270725792-581-1-git-send-email-ext-teemu.3.paasikivi@nokia.com> References: <1270725792-581-1-git-send-email-ext-teemu.3.paasikivi@nokia.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 09 Apr 2010 09:44:16 +0200 Message-ID: <1270799056.3870.1.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2010-04-08 at 14:23 +0300, Teemu Paasikivi wrote: > Added checking of status of scanning to ieee80211_scan_work when hw > scanning is used. It is possible to scan_work get executed while scan > has already been started. Previously this has led to a state where, when > the driver returned EBUSY, the stack aborted scan while hw was left > scanning. That has caused warnings from ieee80211_scan_completed when > the scan actually has been completed. > > Signed-off-by: Teemu Paasikivi > --- > net/mac80211/ieee80211_i.h | 1 + > net/mac80211/scan.c | 8 +++++++- > 2 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h > index 741fb8b..1d14f7c 100644 > --- a/net/mac80211/ieee80211_i.h > +++ b/net/mac80211/ieee80211_i.h > @@ -756,6 +756,7 @@ struct ieee80211_local { > /* Scanning and BSS list */ > struct mutex scan_mtx; > unsigned long scanning; > + bool hw_scan_continue; > struct cfg80211_ssid scan_ssid; > struct cfg80211_scan_request *int_scan_req; > struct cfg80211_scan_request *scan_req, *hw_scan_req; > diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c > index 75a8597..4e4bad0 100644 > --- a/net/mac80211/scan.c > +++ b/net/mac80211/scan.c > @@ -265,12 +265,14 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) > > was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); > if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { > + local->hw_scan_continue = true; > ieee80211_queue_delayed_work(&local->hw, > &local->scan_work, 0); > mutex_unlock(&local->scan_mtx); > return; > } > > + local->hw_scan_continue = false; > kfree(local->hw_scan_req); > local->hw_scan_req = NULL; > > @@ -652,7 +654,11 @@ void ieee80211_scan_work(struct work_struct *work) > } > > if (local->hw_scan_req) { > - int rc = drv_hw_scan(local, local->hw_scan_req); > + int rc = 0; > + > + if (!local->scanning || local->hw_scan_continue) > + rc = drv_hw_scan(local, local->hw_scan_req); > + So Luis says he can make something similar happen with SW scan, where we call drv_sw_scan_start twice? johannes