From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753577AbdDJOMJ convert rfc822-to-8bit (ORCPT ); Mon, 10 Apr 2017 10:12:09 -0400 Received: from smtp-out6.electric.net ([192.162.217.195]:53843 "EHLO smtp-out6.electric.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752760AbdDJOMH (ORCPT ); Mon, 10 Apr 2017 10:12:07 -0400 From: David Laight To: "'Matthias Kaehlcke'" , Johannes Berg , "David S . Miller" CC: "linux-kernel@vger.kernel.org" , "linux-wireless@vger.kernel.org" , "netdev@vger.kernel.org" , Grant Grundler , Michael Davidson , Greg Hackmann Subject: RE: [PATCH] mac80211: Fix clang warning about constant operand in logical operation Thread-Topic: [PATCH] mac80211: Fix clang warning about constant operand in logical operation Thread-Index: AQHSrweh23WBMftlukyE+vsIOfbfxaG+qinw Date: Mon, 10 Apr 2017 14:12:00 +0000 Message-ID: <063D6719AE5E284EB5DD2968C1650D6DCFFCA9CE@AcuExch.aculab.com> References: <20170406185633.91065-1-mka@chromium.org> In-Reply-To: <20170406185633.91065-1-mka@chromium.org> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.202.99.200] Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-Outbound-IP: 213.249.233.130 X-Env-From: David.Laight@ACULAB.COM X-Proto: esmtps X-Revdns: X-HELO: AcuExch.aculab.com X-TLS: TLSv1:AES128-SHA:128 X-Authenticated_ID: X-PolicySMART: 3396946, 3397078 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Matthias Kaehlcke > Sent: 06 April 2017 19:57 > Clang raises a warning about the expression 'strlen(CONFIG_XXX)' being > used in a logical operation. Clangs' builtin strlen function resolves the > expression to a constant at compile time, which causes clang to generate > a 'constant-logical-operand' warning. > > Split the if statement in two to avoid using the const expression in a > logical operation. > > Signed-off-by: Matthias Kaehlcke > --- > net/mac80211/rate.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c > index 206698bc93f4..68ff202d6380 100644 > --- a/net/mac80211/rate.c > +++ b/net/mac80211/rate.c > @@ -173,9 +173,14 @@ ieee80211_rate_control_ops_get(const char *name) > /* try default if specific alg requested but not found */ > ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo); > > + if (ops) > + goto unlock; > + > /* try built-in one if specific alg requested but not found */ > - if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT)) > + if (strlen(CONFIG_MAC80211_RC_DEFAULT)) > ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT); > + > +unlock: Using the result of strlen() as a boolean should itself be a compilation error. You could change to code to the equivalent: if (!ops && CONFIG_MAC80211_RC_DEFAULT[0]) ops = ... David