From e1534ae95004d6a307839a44eed40389d608c935 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Fri, 15 Jan 2016 16:53:46 -0800
Subject: mm: differentiate page_mapped() from page_mapcount() for compound
 pages

Let's define page_mapped() to be true for compound pages if any
sub-pages of the compound page is mapped (with PMD or PTE).

On other hand page_mapcount() return mapcount for this particular small
page.

This will make cases like page_get_anon_vma() behave correctly once we
allow huge pages to be mapped with PTE.

Most users outside core-mm should use page_mapcount() instead of
page_mapped().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 arch/sh/mm/cache-sh4.c | 2 +-
 arch/sh/mm/cache.c     | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

(limited to 'arch/sh/mm')

diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index 51d8f7f31d1d..58aaa4f33b81 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -241,7 +241,7 @@ static void sh4_flush_cache_page(void *args)
 		 */
 		map_coherent = (current_cpu_data.dcache.n_aliases &&
 			test_bit(PG_dcache_clean, &page->flags) &&
-			page_mapped(page));
+			page_mapcount(page));
 		if (map_coherent)
 			vaddr = kmap_coherent(page, address);
 		else
diff --git a/arch/sh/mm/cache.c b/arch/sh/mm/cache.c
index f770e3992620..e58cfbf45150 100644
--- a/arch/sh/mm/cache.c
+++ b/arch/sh/mm/cache.c
@@ -59,7 +59,7 @@ void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 		       unsigned long vaddr, void *dst, const void *src,
 		       unsigned long len)
 {
-	if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
+	if (boot_cpu_data.dcache.n_aliases && page_mapcount(page) &&
 	    test_bit(PG_dcache_clean, &page->flags)) {
 		void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
 		memcpy(vto, src, len);
@@ -78,7 +78,7 @@ void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
 			 unsigned long vaddr, void *dst, const void *src,
 			 unsigned long len)
 {
-	if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
+	if (boot_cpu_data.dcache.n_aliases && page_mapcount(page) &&
 	    test_bit(PG_dcache_clean, &page->flags)) {
 		void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
 		memcpy(dst, vfrom, len);
@@ -97,7 +97,7 @@ void copy_user_highpage(struct page *to, struct page *from,
 
 	vto = kmap_atomic(to);
 
-	if (boot_cpu_data.dcache.n_aliases && page_mapped(from) &&
+	if (boot_cpu_data.dcache.n_aliases && page_mapcount(from) &&
 	    test_bit(PG_dcache_clean, &from->flags)) {
 		vfrom = kmap_coherent(from, vaddr);
 		copy_page(vto, vfrom);
@@ -153,7 +153,7 @@ void __flush_anon_page(struct page *page, unsigned long vmaddr)
 	unsigned long addr = (unsigned long) page_address(page);
 
 	if (pages_do_alias(addr, vmaddr)) {
-		if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
+		if (boot_cpu_data.dcache.n_aliases && page_mapcount(page) &&
 		    test_bit(PG_dcache_clean, &page->flags)) {
 			void *kaddr;
 
-- 
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