Commit 1e75529e authored Nov 16, 2012 by Miao Xie Committed by Al Viro Dec 20, 2012

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 <miaox@cn.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent f01af9f8

fs/namespace.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

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