From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 25 Apr 2025 21:24:10 +0000 (-0400)
Subject: combine __put_mountpoint() with unhash_mnt()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=86f63980964b334ad49d5c1f132f3b9491303a15;p=thirdparty%2Flinux.git

combine __put_mountpoint() with unhash_mnt()

A call of unhash_mnt() is immediately followed by passing its return
value to __put_mountpoint(); the shrink list given to __put_mountpoint()
will be ex_mountpoints when called from umount_mnt() and list when called
from mntput_no_expire().

Replace with __umount_mnt(mount, shrink_list), moving the call of
__put_mountpoint() into it (and returning nothing), adjust the
callers.

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 eee73e945a540..521ffa52c9063 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1037,9 +1037,9 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns)
 }
 
 /*
- * vfsmount lock must be held for write
+ * locks: mount_lock[write_seqlock]
  */
-static struct mountpoint *unhash_mnt(struct mount *mnt)
+static void __umount_mnt(struct mount *mnt, struct list_head *shrink_list)
 {
 	struct mountpoint *mp;
 	struct mount *parent = mnt->mnt_parent;
@@ -1052,15 +1052,15 @@ static struct mountpoint *unhash_mnt(struct mount *mnt)
 	hlist_del_init(&mnt->mnt_mp_list);
 	mp = mnt->mnt_mp;
 	mnt->mnt_mp = NULL;
-	return mp;
+	__put_mountpoint(mp, shrink_list);
 }
 
 /*
- * vfsmount lock must be held for write
+ * locks: mount_lock[write_seqlock], namespace_sem[excl] (for ex_mountpoints)
  */
 static void umount_mnt(struct mount *mnt)
 {
-	put_mountpoint(unhash_mnt(mnt));
+	__umount_mnt(mnt, &ex_mountpoints);
 }
 
 /*
@@ -1451,7 +1451,7 @@ static void mntput_no_expire(struct mount *mnt)
 	if (unlikely(!list_empty(&mnt->mnt_mounts))) {
 		struct mount *p, *tmp;
 		list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts,  mnt_child) {
-			__put_mountpoint(unhash_mnt(p), &list);
+			__umount_mnt(p, &list);
 			hlist_add_head(&p->mnt_umount, &mnt->mnt_stuck_children);
 		}
 	}