From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 21 Aug 2025 00:22:10 +0000 (-0400)
Subject: put_mnt_ns(): use guards
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=61e68af33ac7977ea2457a861ab8eeb2406cb3f1;p=users%2Fhch%2Fmisc.git

put_mnt_ns(): use guards

clean fit; guards can't be weaker due to umount_tree() call.
Setting emptied_ns requires namespace_excl, but not anything
mount_lock-related.

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 898a6b7307e4..86a86be2b0ef 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -6153,12 +6153,10 @@ void put_mnt_ns(struct mnt_namespace *ns)
 {
 	if (!refcount_dec_and_test(&ns->ns.count))
 		return;
-	namespace_lock();
+	guard(namespace_excl)();
 	emptied_ns = ns;
-	lock_mount_hash();
+	guard(mount_writer)();
 	umount_tree(ns->root, 0);
-	unlock_mount_hash();
-	namespace_unlock();
 }
 
 struct vfsmount *kern_mount(struct file_system_type *type)