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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2014-08-13 12:32:02 +0530 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-08-13 18:20:41 +1000 |
| commit | 7e467245bf5226db34c4b12d3cbacfa2f7a15a8b (patch) | |
| tree | 943f6aa4fe6c82e64372cbac2f5e2f94dc015419 | |
| parent | 969b7b208f7408712a3526856e4ae60ad13f6928 (diff) | |
| download | keystone-7e467245bf5226db34c4b12d3cbacfa2f7a15a8b.tar.gz | |
powerpc/thp: Use ACCESS_ONCE when loading pmdp
We would get wrong results in compiler recomputed old_pmd. Avoid
that by using ACCESS_ONCE
CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -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 1fb609dcc49b2..5f5e6328c21c1 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; |