Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760143Ab1D1PtA (ORCPT ); Thu, 28 Apr 2011 11:49:00 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:41511 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754951Ab1D1Ps7 convert rfc822-to-8bit (ORCPT ); Thu, 28 Apr 2011 11:48:59 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=bcLEmhzVng6xrhb/ci302lUS5DzoY7ZKG11bbjnfyUDLt5zDyi92WjzxhhbspwqW0r SUfN7pJcaXfOpJNrc4Zg78hLko7BhCY9QP5Uiz2wXCwOKf6KftdzFEHTv3wufFrv0O7v E+HydnlCAUeFYNlTZtjGNutzapJQci/Mcn9R0= MIME-Version: 1.0 In-Reply-To: <20110429004505.3D7F.A69D9226@jp.fujitsu.com> References: <20110429002847.3D77.A69D9226@jp.fujitsu.com> <20110429004505.3D7F.A69D9226@jp.fujitsu.com> Date: Thu, 28 Apr 2011 12:48:58 -0300 Message-ID: Subject: Re: [PATCH v3] cpumask: add cpumask_var_t documentation From: Thiago Farina To: KOSAKI Motohiro Cc: LKML , Andrew Morton Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3747 Lines: 126 On Thu, Apr 28, 2011 at 12:43 PM, KOSAKI Motohiro wrote: >> On Thu, Apr 28, 2011 at 12:27 PM, KOSAKI Motohiro >> wrote: >> > cpumask_var_t has one nortable difference against cpumask_t. >> > This patch adds the explanation. >> > >> > Signed-off-by: KOSAKI Motohiro >> > --- >> >  include/linux/cpumask.h |   14 ++++++++++++++ >> >  1 files changed, 14 insertions(+), 0 deletions(-) >> > >> > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h >> > index 1e40dd0..471c98a 100644 >> > --- a/include/linux/cpumask.h >> > +++ b/include/linux/cpumask.h >> > @@ -617,6 +617,20 @@ static inline size_t cpumask_size(void) >> >  *       ... use 'tmpmask' like a normal struct cpumask * ... >> >  * >> >  *     free_cpumask_var(tmpmask); >> > + * >> > + * >> > + * However, one notable exception is there. cpumask_var_t is allocated >> > + * only nr_cpu_ids bits >> >> Maybe, instead of "is allocated only", "allocates only" ? > > Instead, "alloc_cpumask_var() allocates only nr_cpu_ids bits" is more clear? :) > Yup. Thx. > >> > (in the other hand, real cpumask_t always has >> > + * NR_CPUS bits). therefore You don't have to dereference cpumask_var_t. >> >> s/therefore You/Therefore you/ ? >> > > Thx. > > >> > + * >> > + *     cpumask_var_t tmpmask; >> > + *     if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL)) >> > + *             return -ENOMEM; >> > + * >> > + *     var = *tmpmask; >> > + * >> > + * This code makes NR_CPUS length memcopy and bring memroy corruption. >> >> /s/memroy/memory >> >> You are saying that I should not use this code? I'm confused, could >> you explain a little bit? > > Yes. you aren't confused. > > >> > + * You have to use cpumask_copy() instead. >> >  */ >> >> I don't get this. :( > > "cpumask_copy() privide safe copy functionality." is clear? > Yes. ;) > > From d2ea9d4846e46bcc8a82b9a641ede3a10aca346c Mon Sep 17 00:00:00 2001 > From: KOSAKI Motohiro > Date: Tue, 26 Apr 2011 19:58:39 +0900 > Subject: [PATCH v3] cpumask: add cpumask_var_t documentation > > cpumask_var_t has one nortable difference against cpumask_t. > This patch adds the explanation. > > Signed-off-by: KOSAKI Motohiro > --- >  include/linux/cpumask.h |   14 ++++++++++++++ >  1 files changed, 14 insertions(+), 0 deletions(-) > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > index 1e40dd0..e2b9032 100644 > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -617,6 +617,20 @@ static inline size_t cpumask_size(void) >  *       ... use 'tmpmask' like a normal struct cpumask * ... >  * >  *     free_cpumask_var(tmpmask); > + * > + * > + * However, one notable exception is there. alloc_cpumask_var() allocates > + * only nr_cpumask_bits bits (in the other hand, real cpumask_t always has > + * NR_CPUS bits). Therefore you don't have to dereference cpumask_var_t. > + * > + *     cpumask_var_t tmpmask; > + *     if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL)) > + *             return -ENOMEM; > + * > + *     var = *tmpmask; > + * > + * This code makes NR_CPUS length memcopy and bring memory corruption. Maybe: s/bring memory/brings to a memory/ ? > + * cpumask_copy() privide safe copy functionality. s/privide/provides ? >  */ >  #ifdef CONFIG_CPUMASK_OFFSTACK >  typedef struct cpumask *cpumask_var_t; > -- > 1.7.3.1 > > > > -- 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/