From 1e75529e3c6c18dc535f38454173c4f2dfa99685 Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Fri, 16 Nov 2012 17:23:50 +0800 Subject: [PATCH] vfs, freeze: use ACCESS_ONCE() to guard access to ->mnt_flags The compiler may optimize the while loop and make the check just be done once, so we should use ACCESS_ONCE() to guard access to ->mnt_flags Signed-off-by: Miao Xie Signed-off-by: Al Viro --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 398a50ff2438..55605c552787 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -313,7 +313,7 @@ int __mnt_want_write(struct vfsmount *m) * incremented count after it has set MNT_WRITE_HOLD. */ smp_mb(); - while (mnt->mnt.mnt_flags & MNT_WRITE_HOLD) + while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) cpu_relax(); /* * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will -- 2.20.1