From: Mateusz Guzik <mjguzik@gmail.com>
Date: Wed, 4 Oct 2023 11:19:16 +0000 (+0200)
Subject: vfs: stop counting on gcc not messing with mnt_expiry_mark if not asked
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6c4d1c99d2ad5e12b897da482ca8305b929cb9ce;p=linux.git

vfs: stop counting on gcc not messing with mnt_expiry_mark if not asked

So happens it already was not doing it, but there is no need to "hope"
as indicated in the comment.

No changes in generated assembly.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20231004111916.728135-3-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
---

diff --git a/fs/namespace.c b/fs/namespace.c
index 9e0ea73f2ff91..6bde71735efa7 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1346,9 +1346,9 @@ void mntput(struct vfsmount *mnt)
 {
 	if (mnt) {
 		struct mount *m = real_mount(mnt);
-		/* avoid cacheline pingpong, hope gcc doesn't get "smart" */
+		/* avoid cacheline pingpong */
 		if (unlikely(m->mnt_expiry_mark))
-			m->mnt_expiry_mark = 0;
+			WRITE_ONCE(m->mnt_expiry_mark, 0);
 		mntput_no_expire(m);
 	}
 }