Return-path: Received: from rv-out-0910.google.com ([209.85.198.186]:43292 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758294AbYCEGts (ORCPT ); Wed, 5 Mar 2008 01:49:48 -0500 Received: by rv-out-0910.google.com with SMTP id k20so798383rvb.1 for ; Tue, 04 Mar 2008 22:49:47 -0800 (PST) Message-ID: <70318cbf0803042249j57d7f3a3j7666961a9132b10b@mail.gmail.com> (sfid-20080305_064954_860134_CB37A934) 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 References: <20080305063842.GA24495@elte.hu> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 >