sysfs, kernfs: no need to kern_mount() sysfs from sysfs_init()

It has been very long since sysfs depended on vfs to keep track of
internal states and whether sysfs is mounted or not doesn't make any
difference to sysfs's internal operation.

In addition to init and filesystem type registration, sysfs_init()
invokes kern_mount() to create in-kernel mount of sysfs.  This
internal mounting doesn't server any purpose anymore.  Remove it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/sysfs/mount.c

@@ -24,7 +24,6 @@
 #include "sysfs.h"
 
 
-static struct vfsmount *sysfs_mnt;
 struct kmem_cache *sysfs_dir_cachep;
 
 static const struct super_operations sysfs_ops = {
@@ -153,34 +152,26 @@ static struct file_system_type sysfs_fs_type = {
 
 int __init sysfs_init(void)
 {
-	int err = -ENOMEM;
+	int err;
 
 	sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
 					      sizeof(struct sysfs_dirent),
 					      0, 0, NULL);
 	if (!sysfs_dir_cachep)
-		goto out;
+		return -ENOMEM;
 
 	err = sysfs_inode_init();
 	if (err)
 		goto out_err;
 
 	err = register_filesystem(&sysfs_fs_type);
-	if (!err) {
-		sysfs_mnt = kern_mount(&sysfs_fs_type);
-		if (IS_ERR(sysfs_mnt)) {
-			printk(KERN_ERR "sysfs: could not mount!\n");
-			err = PTR_ERR(sysfs_mnt);
-			sysfs_mnt = NULL;
-			unregister_filesystem(&sysfs_fs_type);
-			goto out_err;
-		}
-	} else
+	if (err)
 		goto out_err;
-out:
-	return err;
+
+	return 0;
+
 out_err:
 	kmem_cache_destroy(sysfs_dir_cachep);
 	sysfs_dir_cachep = NULL;
-	goto out;
+	return err;
 }