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@xxxxxxxxxxxxxx> --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 7bdf790..6eca68e 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -311,7 +311,7 @@ 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 -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
