| Message ID | 1421312314-72330-6-git-send-email-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Michael Ellerman |
| Headers | show |
diff --git a/mm/gup.c b/mm/gup.c index a900759..bed30efa 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -926,7 +926,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, pmdp = pmd_offset(&pud, addr); do { - pmd_t pmd = ACCESS_ONCE(*pmdp); + pmd_t pmd = READ_ONCE(*pmdp); next = pmd_addr_end(addr, end); if (pmd_none(pmd) || pmd_trans_splitting(pmd))
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) Fixup gup_pmd_range. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- mm/gup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)