Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763582AbYCEGuH (ORCPT ); Wed, 5 Mar 2008 01:50:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758943AbYCEGtu (ORCPT ); Wed, 5 Mar 2008 01:49:50 -0500 Received: from rv-out-0910.google.com ([209.85.198.187]:42640 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758125AbYCEGtr (ORCPT ); Wed, 5 Mar 2008 01:49:47 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=rR5p014WEeTPF5ZdoHAaARcqI5WaF0s79L9hdLXc9cdjrZezp7nllDlPL16oQkshK5WYJpwBJqJujAc/mz/ePuyxukL0L/TxTJul/kRteEUig+bevY/bKaGShRt3QvzzhcVrQyc9bWMGR16Orde/RyA1mG02vP/sjCVuowx7cSA= Message-ID: <70318cbf0803042249j57d7f3a3j7666961a9132b10b@mail.gmail.com> Date: Tue, 4 Mar 2008 22:49:47 -0800 From: "Christopher Li" To: "Ingo Molnar" Subject: Re: [PATCH 6/9] drivers/net/wireless/iwlwifi/iwl-4965.c: Correct use of ! and & Cc: "Julia Lawall" , yi.zhu@intel.com, linux-wireless@vger.kernel.org, ipw3945-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, "Harvey Harrison" , "Alexander Viro" , linux-sparse@vger.kernel.org, "Josh Triplett" In-Reply-To: <20080305063842.GA24495@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080305063842.GA24495@elte.hu> X-Google-Sender-Auth: 425f03b5bdbb20f8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1723 Lines: 47 I think Al Viro has sent a patch to linux-sparse with subject "[PATCH 3/3] catch !x & y brainos" does exactly that. Chris On Tue, Mar 4, 2008 at 10:38 PM, Ingo Molnar wrote: > > * Julia Lawall wrote: > > > From: Julia Lawall > > > > In commit e6bafba5b4765a5a252f1b8d31cbf6d2459da337, a bug was fixed > > that involved converting !x & y to !(x & y). The code below shows the > > same pattern, and thus should perhaps be fixed in the same way. > > > > if (sta_ht_inf) { > > if ((!sta_ht_inf->ht_supported) || > > - (!sta_ht_inf->cap & IEEE80211_HT_CAP_SUP_WIDTH)) > > + (!(sta_ht_inf->cap & IEEE80211_HT_CAP_SUP_WIDTH))) > > return 0; > > i'm wondering, could Sparse be extended to check for such patterns? > > People are regularly running "make C=1" and are sending fixes to make > entire subsystems sparse-warning-free, so Sparse is a nice mechanism > that works and it keeps code clean in the long run. > > I dont think the "!X & Y" pattern is ever used legitimately [and even if > it were used legitimately, it's easy to avoid the sparse false positive > - while in the buggy case we have a clear bug]. > > Ingo > -- > To unsubscribe from this list: send the line "unsubscribe linux-sparse" in > > > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/