Commit 38c5ce93 authored Jan 06, 2015 by Christian Borntraeger

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 <borntraeger@de.ibm.com>

parent bccec2a0

mm/gup.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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))