]> git.karo-electronics.de Git - linux-beck.git/commitdiff
mm/gup: Replace ACCESS_ONCE with READ_ONCE
authorChristian Borntraeger <borntraeger@de.ibm.com>
Tue, 6 Jan 2015 21:54:46 +0000 (22:54 +0100)
committerChristian Borntraeger <borntraeger@de.ibm.com>
Mon, 19 Jan 2015 13:14:21 +0000 (14:14 +0100)
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

index a900759cc8075fc8b0da9a37ebf6f93de34d8d10..bed30efad77cde82edc22af7bb21b51fa88e88d3 100644 (file)
--- 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))