Re: [PATCH] hugetlbfs: add err code in initializing module

Hillf Danton
2012-03-22T13:26:14Z

On Thu, Mar 22, 2012 at 8:33 AM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Sun, Mar 11, 2012 at 01:09:59PM +0800, Hillf Danton wrote:
>> 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.
>>
>> --- a/fs/hugetlbfs/inode.c    Sun Mar 11 12:46:38 2012
>> +++ b/fs/hugetlbfs/inode.c    Sun Mar 11 12:49:28 2012
>> @@ -1000,6 +1000,7 @@ static int __init init_hugetlbfs_fs(void
>>       hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
>>                                       sizeof(struct hugetlbfs_inode_info),
>>                                       0, 0, init_once);
>> +     error = -ENOMEM;
>>       if (hugetlbfs_inode_cachep == NULL)
>>               goto out2;
>>
>> @@ -1015,6 +1016,7 @@ static int __init init_hugetlbfs_fs(void
>>       }
>>
>>       error = PTR_ERR(vfsmount);
>> +     unregister_filesystem(&hugetlbfs_fs_type);
>
> Bloody bad idea, that...  Realistically, the proper action on failure here
> (as well as in sock_init(), etc.) is panic().  If we fail to OOM that early,
> the box is doomed anyway.
>
> Note that unregister_filesystem() in module init is *always* wrong; it's not
> an issue here (it's done too early to care about and realistically the box
> is not going anywhere - it'll panic when attempt to exec /sbin/init fails,
> if not earlier), but it's a damn bad example.
>
Thanks for your review, Al.

Due to bad idea and bad example, please issue Nack, then the patch
that was not well prepared will be dropped.

-hd