diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2014-08-13 12:32:02 +0530 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-09-17 16:55:05 +0200 |
| commit | 9de1fa60881dc08bd562aa3b1a31e42829eb8dd1 (patch) | |
| tree | c0c359b1771aa96d93a6ac67c167a103c85d53b5 /arch | |
| parent | 5611f07c012a8174a1cd5c9b3ced93810d479989 (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: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'arch')
| -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 e0da84719b46..7d86c868040d 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; |