From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755164Ab2HMWGP (ORCPT ); Mon, 13 Aug 2012 18:06:15 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:42231 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755138Ab2HMWGB (ORCPT ); Mon, 13 Aug 2012 18:06:01 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Johannes Berg Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Liang Li , Paul Gortmaker Subject: [ 41/44] cfg80211: fix interface combinations check for ADHOC(IBSS) Date: Mon, 13 Aug 2012 15:02:48 -0700 Message-Id: <20120813220145.760434381@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120813220142.113186818@linuxfoundation.org> References: <20120813220142.113186818@linuxfoundation.org> User-Agent: quilt/0.60-20.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liang Li partial of commit 8e8b41f9d8c8e63fc92f899ace8da91a490ac573 upstream. As part of commit 463454b5dbd8 ("cfg80211: fix interface combinations check"), this extra check was introduced: if ((all_iftypes & used_iftypes) != used_iftypes) goto cont; However, most wireless NIC drivers did not advertise ADHOC in wiphy.iface_combinations[i].limits[] and hence we'll get -EBUSY when we bring up a ADHOC wlan with commands similar to: # iwconfig wlan0 mode ad-hoc && ifconfig wlan0 up In commit 8e8b41f9d8c8e ("cfg80211: enforce lack of interface combinations"), the change below fixes the issue: if (total == 1) return 0; But it also introduces other dependencies for stable. For example, a full cherry pick of 8e8b41f9d8c8e would introduce additional regressions unless we also start cherry picking driver specific fixes like the following: 9b4760e ath5k: add possible wiphy interface combinations 1ae2fc2 mac80211_hwsim: advertise interface combinations 20c8e8d ath9k: add possible wiphy interface combinations And the purpose of the 'if (total == 1)' is to cover the specific use case (IBSS, adhoc) that was mentioned above. So we just pick the specific part out from 8e8b41f9d8c8e here. Doing so gives stable kernels a way to fix the change introduced by 463454b5dbd8, without having to make cherry picks specific to various NIC drivers. Signed-off-by: Liang Li Signed-off-by: Paul Gortmaker Signed-off-by: Greg Kroah-Hartman --- net/wireless/util.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -975,6 +975,9 @@ int cfg80211_can_change_interface(struct } mutex_unlock(&rdev->devlist_mtx); + if (total == 1) + return 0; + for (i = 0; i < rdev->wiphy.n_iface_combinations; i++) { const struct ieee80211_iface_combination *c; struct ieee80211_iface_limit *limits;