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ppc/hugetlbfs: Replace ACCESS_ONCE with READ_ONCE 

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the ppc/hugetlbfs code to replace ACCESS_ONCE with READ_ONCE.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Christian Borntraeger 2015-01-06 22:47:41 +01:00
parent 5ee07612e9
commit da1a288d85
1 changed files with 2 additions and 2 deletions
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4
arch/powerpc/mm/hugetlbpage.c
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@ -978,7 +978,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
*/
pdshift = PUD_SHIFT;
pudp = pud_offset(&pgd, ea);
pud = ACCESS_ONCE(*pudp);
pud = READ_ONCE(*pudp);
if (pud_none(pud))
return NULL;
@ -990,7 +990,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
else {
pdshift = PMD_SHIFT;
pmdp = pmd_offset(&pud, ea);
pmd = ACCESS_ONCE(*pmdp);
pmd = READ_ONCE(*pmdp);
/*
* A hugepage collapse is captured by pmd_none, because
* it mark the pmd none and do a hpte invalidate.