From 9d8c47e4bb1c20dbceee437f9fa7d76dafee80a2 Mon Sep 17 00:00:00 2001
From: Jason Low <jason.low2@hp.com>
Date: Wed, 15 Apr 2015 16:14:05 -0700
Subject: [PATCH] mm: use READ_ONCE() for non-scalar types
Commit 38c5ce936a08 ("mm/gup: Replace ACCESS_ONCE with READ_ONCE")
converted ACCESS_ONCE usage in gup_pmd_range() to READ_ONCE, since
ACCESS_ONCE doesn't work reliably on non-scalar types.
This patch also fixes the other ACCESS_ONCE usages in gup_pte_range()
and __get_user_pages_fast() in mm/gup.c
Signed-off-by: Jason Low <jason.low2@hp.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/gup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index ca7b607ab671..6297f6bccfb1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1019,7 +1019,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
*
* for an example see gup_get_pte in arch/x86/mm/gup.c
*/
- pte_t pte = ACCESS_ONCE(*ptep);
+ pte_t pte = READ_ONCE(*ptep);
struct page *page;
/*
@@ -1309,7 +1309,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
local_irq_save(flags);
pgdp = pgd_offset(mm, addr);
do {
- pgd_t pgd = ACCESS_ONCE(*pgdp);
+ pgd_t pgd = READ_ONCE(*pgdp);
next = pgd_addr_end(addr, end);
if (pgd_none(pgd))
--
2.34.1