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| author | Miao Xie <miaox@cn.fujitsu.com> | 2012-11-16 17:23:50 +0800 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-12-20 13:36:18 -0500 |
| commit | 1e75529e3c6c18dc535f38454173c4f2dfa99685 (patch) | |
| tree | e875baa006457bdffd536fe97fffe03078c91c4f | |
| parent | f01af9f85855e38fbd601e033a8eac204cc4cc1c (diff) | |
| download | lwn-1e75529e3c6c18dc535f38454173c4f2dfa99685.tar.gz lwn-1e75529e3c6c18dc535f38454173c4f2dfa99685.zip | |
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>
| -rw-r--r-- | fs/namespace.c | 2 |
1 files changed, 1 insertions, 1 deletions
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 |