hugetlbfs: remove unregister_filesystem() when initializing module

It was introduced by d1d5e05ffdc1 ("hugetlbfs: return error code when
initializing module") but as Al pointed out, is a bad idea.

Quoted comments from Al:
 "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.

  Consider a normal fs module.  Somebody loads it and in parallel with
  that we get a mount attempt on that fs type.  It comes between
  register and failure exits that causes unregister; at that point we
  are screwed since grabbing a reference to module as done by mount is
  enough to prevent exit, but not to prevent the failure of init.  As
  the result, module will get freed when init fails, mounted fs of that
  type be damned."

So remove it.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index ea251749d9d5982e6fc35ecf6d21ab61547962e8..28cf06e4ec8466478ce34db5db271f179dc0d7b5 100644 (file)
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -1031,7 +1031,6 @@ static int __init init_hugetlbfs_fs(void)
        }
 
        error = PTR_ERR(vfsmount);
-       unregister_filesystem(&hugetlbfs_fs_type);
 
  out:
        kmem_cache_destroy(hugetlbfs_inode_cachep);