From patchwork Sat Nov 30 20:39:00 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Perches X-Patchwork-Id: 3260901 Return-Path: X-Original-To: patchwork-linux-wireless@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EDAE5BEEAE for ; Sat, 30 Nov 2013 20:39:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2E2982046F for ; Sat, 30 Nov 2013 20:39:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4144320480 for ; Sat, 30 Nov 2013 20:39:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751426Ab3K3UjY (ORCPT ); Sat, 30 Nov 2013 15:39:24 -0500 Received: from smtprelay0137.hostedemail.com ([216.40.44.137]:49483 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751259Ab3K3UjF (ORCPT ); Sat, 30 Nov 2013 15:39:05 -0500 Received: from filter.hostedemail.com (ff-bigip1 [10.5.19.254]) by smtprelay03.hostedemail.com (Postfix) with ESMTP id 92C5E6B5A8; Sat, 30 Nov 2013 20:39:04 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2, 0, 0, , d41d8cd98f00b204, joe@perches.com, :::::::::::::::, RULES_HIT:41:355:379:541:599:973:981:988:989:1260:1261:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1543:1593:1594:1711:1730:1747:1777:1792:1963:2393:2553:2559:2562:2692:2828:2893:3138:3139:3140:3141:3142:3355:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:4250:4321:5007:7652:7809:7875:7903:9036:10004:10400:10471:10848:11026:11232:11473:11658:11914:12043:12296:12438:12517:12519:12555:12663:12740:13161:13229:13255, 0, RBL:none, CacheIP:none, Bayesian:0.5, 0.5, 0.5, Netcheck:none, DomainCache:0, MSF:not bulk, SPF:fn, MSBL:0, DNSBL:none, Custom_rules:0:0:0 X-HE-Tag: salt42_89256baa87b63 X-Filterd-Recvd-Size: 4775 Received: from [192.168.1.157] (pool-96-251-49-11.lsanca.fios.verizon.net [96.251.49.11]) (Authenticated sender: joe@perches.com) by omf10.hostedemail.com (Postfix) with ESMTPA; Sat, 30 Nov 2013 20:39:02 +0000 (UTC) Message-ID: <1385843940.2664.4.camel@joe-AO722> Subject: Re: [PATCH] net: mac80211: tx.c: be sure of 'sdata->vif.type' must be NL80211_IFTYPE_AP when be in NL80211_IFTYPE_AP case From: Joe Perches To: Johannes Berg Cc: Chen Gang , "John W. Linville" , rkuo , "linux-kernel@vger.kernel.org" , David Miller , linux-wireless@vger.kernel.org, netdev Date: Sat, 30 Nov 2013 12:39:00 -0800 In-Reply-To: <1385842134.6108.4.camel@jlt4.sipsolutions.net> References: <528AEFB7.4060301@gmail.com> <20131125011938.GB18921@codeaurora.org> <5292B845.3010404@gmail.com> <5292B8A0.7020409@gmail.com> <5294255E.7040105@gmail.com> <52957ADA.2080704@gmail.com> (sfid-20131127_055211_558798_A7DF5684) <1385739487.8656.1.camel@jlt4.sipsolutions.net> <5299D306.7070701@gmail.com> (sfid-20131130_125901_519610_EDA4068E) <1385816013.4327.1.camel@jlt4.sipsolutions.net> <5299ED38.4090509@gmail.com> <5299EFDD.6060405@gmail.com> (sfid-20131130_150205_984535_068F14A9) <1385842134.6108.4.camel@jlt4.sipsolutions.net> X-Mailer: Evolution 3.8.4-0ubuntu1 Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Sat, 2013-11-30 at 21:08 +0100, Johannes Berg wrote: > On Sat, 2013-11-30 at 22:02 +0800, Chen Gang wrote: > > > >>> case NL80211_IFTYPE_AP: > > >>> - if (sdata->vif.type == NL80211_IFTYPE_AP) > > >>> - chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); > > >>> + chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); > > >>> if (!chanctx_conf) > > >>> goto fail_rcu; > > >>> +try_next: > > >> > > >> I don't think that's better than the (fairly obvious) fall-through, and > > >> has a pretty odd goto. Also, depending on the compiler, it still knows > > >> the previous case label and doesn't warn. > > >> > > > > > > Yeah, fall-through is obvious. But check 'A' again just near by "case A" > > > seems a little strange, and some of compilers (or some of versions) are > > > really not quit smart enough to know it is not a warning. > > > > > > > Sorry, the paragraph above may lead misunderstanding, I repeated again: > > > > - fall-through is obvious (although I did not notice it, originally). > > > > - Check 'A' again just near by "case A" seems a little strange. > > > > - Some compilers aren't quit smart enough to know 'chanctx_conf' is OK. > > I know. If you have any good ideas of how to make it more obvious to the > compiler, I'm all ears, I just don't like any of the solutions offered > so far (and you aren't the first to do so either) :-) > > FWIW, I find the label to be odd because if you're familiar with the > code then AP/AP_VLAN *should* be identical except for two special things > that are now linearly & neatly handled in the code (the first being the > 4-addr station, the second the chanctx assignment which always has to be > done regardless of 4-addr). IMHO the == check after case should be > enough to make a human reader take a closer look. I understand that you > didn't and that's OK since you were just trying to squelch compile > warnings, but I don't see that this one warrants much attention. The label/test could be moved to save a couple of lines of duplicated code. Maybe: net/mac80211/tx.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) --- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 70b5a05..b2160f4 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1777,18 +1777,16 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb, } ap_sdata = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap); - chanctx_conf = rcu_dereference(ap_sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; - band = chanctx_conf->def.chan->band; - if (sta) - break; /* fall through */ case NL80211_IFTYPE_AP: - if (sdata->vif.type == NL80211_IFTYPE_AP) - chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); + chanctx_conf = rcu_dereference(ap_sdata->vif.chanctx_conf); if (!chanctx_conf) goto fail_rcu; + if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) { + band = chanctx_conf->def.chan->band; + if (sta) + break; + } fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS); /* DA BSSID SA */ memcpy(hdr.addr1, skb->data, ETH_ALEN);