get rid of mnt_set_mountpoint_beneath()

mnt_set_mountpoint_beneath() consists of attaching new mount side-by-side
with the one we want to mount beneath (by mnt_set_mountpoint()), followed
by mnt_change_mountpoint() shifting the the top mount onto the new one
(by mnt_change_mountpoint()).

Both callers of mnt_set_mountpoint_beneath (both in attach_recursive_mnt())
have the same form - in 'beneath' case we call mnt_set_mountpoint_beneath(),
otherwise - mnt_set_mountpoint().

The thing is, expressing that as unconditional mnt_set_mountpoint(),
followed, in 'beneath' case, by mnt_change_mountpoint() is just as easy.
And these mnt_change_mountpoint() callers are similar to the ones we
do when it comes to attaching propagated copies, which will allow more
cleanups in the next commits.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namespace.c b/fs/namespace.c
index 1761d2c2fdae60706ef773cbb969f361e9705b62..888816289154b03de6bf13069f7ebbb1c19fa2bd 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1076,33 +1076,6 @@ void mnt_set_mountpoint(struct mount *mnt,
        hlist_add_head(&child_mnt->mnt_mp_list, &mp->m_list);
 }
 
-/**
- * mnt_set_mountpoint_beneath - mount a mount beneath another one
- *
- * @new_parent: the source mount
- * @top_mnt:    the mount beneath which @new_parent is mounted
- * @new_mp:     the new mountpoint of @top_mnt on @new_parent
- *
- * Remove @top_mnt from its current mountpoint @top_mnt->mnt_mp and
- * parent @top_mnt->mnt_parent and mount it on top of @new_parent at
- * @new_mp. And mount @new_parent on the old parent and old
- * mountpoint of @top_mnt.
- *
- * Context: This function expects namespace_lock() and lock_mount_hash()
- *          to have been acquired in that order.
- */
-static void mnt_set_mountpoint_beneath(struct mount *new_parent,
-                                      struct mount *top_mnt,
-                                      struct mountpoint *new_mp)
-{
-       struct mount *old_top_parent = top_mnt->mnt_parent;
-       struct mountpoint *old_top_mp = top_mnt->mnt_mp;
-
-       mnt_set_mountpoint(old_top_parent, old_top_mp, new_parent);
-       mnt_change_mountpoint(new_parent, new_mp, top_mnt);
-}
-
-
 static void __attach_mnt(struct mount *mnt, struct mount *parent)
 {
        hlist_add_head_rcu(&mnt->mnt_hash,
@@ -2729,10 +2702,9 @@ static int attach_recursive_mnt(struct mount *source_mnt,
 
        if (moving) {
                unhash_mnt(source_mnt);
+               mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
                if (beneath)
-                       mnt_set_mountpoint_beneath(source_mnt, top_mnt, smp);
-               else
-                       mnt_set_mountpoint(top_mnt, dest_mp, source_mnt);
+                       mnt_change_mountpoint(source_mnt, smp, top_mnt);
                __attach_mnt(source_mnt, source_mnt->mnt_parent);
                mnt_notify_add(source_mnt);
                touch_mnt_namespace(source_mnt->mnt_ns);
@@ -2745,10 +2717,9 @@ static int attach_recursive_mnt(struct mount *source_mnt,
                                move_from_ns(p, &head);
                        list_del_init(&head);
                }
+               mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
                if (beneath)
-                       mnt_set_mountpoint_beneath(source_mnt, top_mnt, smp);
-               else
-                       mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
+                       mnt_change_mountpoint(source_mnt, smp, top_mnt);
                commit_tree(source_mnt);
        }