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Date: Mon, 12 Mar 2012 16:58:26 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Hillf Danton <dhillf@gmail.com>
Cc: David Rientjes <rientjes@google.com>, LKML <linux-kernel@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH] hugetlbfs: add err code in initializing module
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On Mon, 12 Mar 2012 20:01:43 +0800
Hillf Danton <dhillf@gmail.com> wrote:

> On Mon, Mar 12, 2012 at 4:25 AM, David Rientjes <rientjes@google.com> wrote:
> >
> > The patch looks good, however, we typically do things like
> >
> > __ __ __ __error = -ENOMEM;
> > __ __ __ __hugetlbfs_inode_cachep = kmem_cache_create(...);
> > __ __ __ __if (!hugetlbfs_inode_cachep)
> > __ __ __ __ __ __ __ __...
> >
> > instead. __Sometimes people grep to see if a call a function that can fail,
> > such as kmem_cache_create(), is followed up by a check for NULL and this
> > would otherwise fail.
> >
> >
> It is updated, thanks David.
> 
> -hd
> ===cut here===
> From: Hillf Danton <dhillf@gmail.com>
> Subject: [PATCH] hugetlbfs: add err code in initilizing module
> 
> Error code is added if fail to create inode kmem cache, and newly registered
> hugetlb FS is unregistered if fail to mount, both for unlikely corner cases.
> 
> Signed-off-by: Hillf Danton <dhillf@gmail.com>
> ---
> 
> --- a/fs/hugetlbfs/inode.c	Sun Mar 11 12:46:38 2012
> +++ b/fs/hugetlbfs/inode.c	Mon Mar 12 19:52:16 2012
> @@ -997,6 +997,7 @@ static int __init init_hugetlbfs_fs(void
>  	if (error)
>  		return error;
> 
> +	error = -ENOMEM;
>  	hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
>  					sizeof(struct hugetlbfs_inode_info),
>  					0, 0, init_once);
> @@ -1015,6 +1016,7 @@ static int __init init_hugetlbfs_fs(void
>  	}
> 
>  	error = PTR_ERR(vfsmount);
> +	unregister_filesystem(&hugetlbfs_fs_type);
> 
>   out:
>  	if (error)

And this, yes?

remove unneeded test of `error'

--- a/fs/hugetlbfs/inode.c~hugetlbfs-return-error-code-when-initializing-module-fix
+++ a/fs/hugetlbfs/inode.c
@@ -1035,8 +1035,7 @@ static int __init init_hugetlbfs_fs(void
 	unregister_filesystem(&hugetlbfs_fs_type);
 
  out:
-	if (error)
-		kmem_cache_destroy(hugetlbfs_inode_cachep);
+	kmem_cache_destroy(hugetlbfs_inode_cachep);
  out2:
 	bdi_destroy(&hugetlbfs_backing_dev_info);
 	return error;
_