Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752552AbaFDLHi (ORCPT ); Wed, 4 Jun 2014 07:07:38 -0400 Received: from mail-ig0-f169.google.com ([209.85.213.169]:45487 "EHLO mail-ig0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751909AbaFDLHf (ORCPT ); Wed, 4 Jun 2014 07:07:35 -0400 MIME-Version: 1.0 In-Reply-To: References: <1401872880-23685-1-git-send-email-Julia.Lawall@lip6.fr> <063D6719AE5E284EB5DD2968C1650D6D1725705F@AcuExch.aculab.com> Date: Wed, 4 Jun 2014 13:07:34 +0200 X-Google-Sender-Auth: IROjYfHMGqWZqhE7r4ymjiAEFqY Message-ID: Subject: Re: [PATCH 0/10] use safer test on the result of find_first_zero_bit From: Geert Uytterhoeven To: Julia Lawall Cc: David Laight , linux-rdma , "kernel-janitors@vger.kernel.org" , Linux Fbdev development list , Linux-sh list , "linux-kernel@vger.kernel.org" , "ath10k@lists.infradead.org" , linux-wireless , "netdev@vger.kernel.org" , driverdevel , "iss_storagedev@hp.com" , scsi , linux-s390 , "adi-buildroot-devel@lists.sourceforge.net" , Arnd Bergmann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Julia, On Wed, Jun 4, 2014 at 1:00 PM, Julia Lawall wrote: > OK, thanks. I was only looking at the C code. > > But the C code contains a loop that is followed by: > > if (!size) > return result; > tmp = *p; > > found_first: > tmp |= ~0UL << size; > if (tmp == ~0UL) /* Are any bits zero? */ > return result + size; /* Nope. */ > > In the first return, it would seem that result == size. Could the second > one be changed to just return size? It should not hurt performance. "size" may have been changed between function entry and this line. So you have to store it in a temporary. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- 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/