From 38c5ce936a0862a6ce2c8d1c72689a3aba301425 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 6 Jan 2015 22:54:46 +0100 Subject: [PATCH] mm/gup: 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) Fixup gup_pmd_range. Signed-off-by: Christian Borntraeger --- mm/gup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index a900759cc807..bed30efad77c 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)) -- 2.39.5