From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756478Ab2IEHPw (ORCPT ); Wed, 5 Sep 2012 03:15:52 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:35007 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750991Ab2IEHPv (ORCPT ); Wed, 5 Sep 2012 03:15:51 -0400 Message-ID: <5046FC22.3050509@gmail.com> Date: Wed, 05 Sep 2012 15:15:46 +0800 From: Cong Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: yan yan CC: akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] proc: return -ENOMEM when inode allocation failed References: <1346681648-21427-1-git-send-email-clouds.yan@gmail.com> <1346681648-21427-2-git-send-email-clouds.yan@gmail.com> <50456F2E.6060408@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/04/2012 05:22 PM, yan yan wrote: > 2012/9/4 Cong Wang : >> On 09/03/2012 10:14 PM, yan wrote: >>> >>> Signed-off-by: yan >> >> >> Please provide a changelog to explain why we need this patch. > > I think the title is self explained. > > >>> --- >>> fs/proc/generic.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/fs/proc/generic.c b/fs/proc/generic.c >>> index b3647fe..9e8f631 100644 >>> --- a/fs/proc/generic.c >>> +++ b/fs/proc/generic.c >>> @@ -427,7 +427,7 @@ struct dentry *proc_lookup_de(struct proc_dir_entry >>> *de, struct inode *dir, >>> if (!memcmp(dentry->d_name.name, de->name, de->namelen)) { >>> pde_get(de); >>> spin_unlock(&proc_subdir_lock); >>> - error = -EINVAL; >>> + error = -ENOMEM; >> >> >> Why the !memcmp() case is related with ENOMEM ?? > > We are presetting 'error' here. The following proc_get_inode() will try > to get an inode, either from inode cache or allocate a new one (and fill it). > > If we get a NULL inode, that means allocation failed. That's how > ENOMEM involved. Then the following patch is probably better than yours: diff --git a/fs/proc/generic.c b/fs/proc/generic.c index b3647fe..6b22913 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -427,12 +427,16 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir, if (!memcmp(dentry->d_name.name, de->name, de->namelen)) { pde_get(de); spin_unlock(&proc_subdir_lock); - error = -EINVAL; inode = proc_get_inode(dir->i_sb, de); + if (!inode) { + error = -ENOMEM; + goto out_put; + } goto out_unlock; } } spin_unlock(&proc_subdir_lock); + out_unlock: if (inode) { @@ -440,6 +444,8 @@ out_unlock: d_add(dentry, inode); return NULL; } +out_put: + if (de) pde_put(de); return ERR_PTR(error);