diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2014-08-13 12:32:02 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-17 09:21:57 -0700 |
| commit | fe86f9f8379957b2ad25c46f496c8d09da288ce7 (patch) | |
| tree | a6920835d98a1bb3a0b2b88a783f2102436f99fb /arch/powerpc/mm | |
| parent | f1a4952b4820a8526ab21b46315d2c9e4656dbed (diff) | |
powerpc/thp: Use ACCESS_ONCE when loading pmdp
commit 7e467245bf5226db34c4b12d3cbacfa2f7a15a8b upstream.
We would get wrong results in compiler recomputed old_pmd. Avoid
that by using ACCESS_ONCE
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/hugepage-hash64.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c index 1fb609dcc49..5f5e6328c21 100644 --- a/arch/powerpc/mm/hugepage-hash64.c +++ b/arch/powerpc/mm/hugepage-hash64.c @@ -84,7 +84,9 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, * atomically mark the linux large page PMD busy and dirty */ do { - old_pmd = pmd_val(*pmdp); + pmd_t pmd = ACCESS_ONCE(*pmdp); + + old_pmd = pmd_val(pmd); /* If PMD busy, retry the access */ if (unlikely(old_pmd & _PAGE_BUSY)) return 0; |