linux-kernel - Re: [PATCH 1/3] proc: return -ENOMEM when inode allocation failed

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Message-ID: <CAH+=+MGaevMRUoF9CKi+YoS4ais3UFJNbQkqRfFBtgjhyWPaeQ@mail.gmail.com>
Date:	Wed, 5 Sep 2012 15:57:54 +0800
From:	yan yan <clouds.yan@...il.com>
To:	Cong Wang <xiyou.wangcong@...il.com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] proc: return -ENOMEM when inode allocation failed

2012/9/5 Cong Wang <xiyou.wangcong@...il.com>:
>>> 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);
>
>

Change so many lines to save a assignment to 'error' ...

That's a stye issue. I prefer a simple change, though your
change seems OK to me.

Thanks
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