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authorArnd Bergmann <arnd@arndb.de>2012-11-15 17:27:43 +0100
committerArnd Bergmann <arnd@arndb.de>2012-11-15 17:27:43 +0100
commit12480c2e53d355223cf6884ed1f56e6ac9b7c21f (patch)
treec244c5b4f265dc38f7658fbe5714ba2c402aef28 /mm/rmap.c
parent6c8e94a57c30e31d0807f038b4f98b659fd67776 (diff)
parent936407358759adb302df93ab61fa68141897270c (diff)
Merge tag 'omap-for-v3.8/fixes-non-critical-v4-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into next/fixes-non-critical
From Tony Lindgren <tony@atomide.com>: Non critical omap fixes that were not considered urgent for the -rc cycle. * tag 'omap-for-v3.8/fixes-non-critical-v4-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap: (645 commits) ARM: OMAP4: PM: fix errata handling when CONFIG_PM=n ARM: OMAP4: retrigger localtimers after re-enabling gic ARM: OMAP4460: Workaround for ROM bug because of CA9 r2pX GIC control register change. ARM: OMAP4: PM: add errata support Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 7df7984d476c..2ee1ef0f317b 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -56,6 +56,7 @@
#include <linux/mmu_notifier.h>
#include <linux/migrate.h>
#include <linux/hugetlb.h>
+#include <linux/backing-dev.h>
#include <asm/tlbflush.h>
@@ -926,11 +927,8 @@ int page_mkclean(struct page *page)
if (page_mapped(page)) {
struct address_space *mapping = page_mapping(page);
- if (mapping) {
+ if (mapping)
ret = page_mkclean_file(mapping, page);
- if (page_test_and_clear_dirty(page_to_pfn(page), 1))
- ret = 1;
- }
}
return ret;
@@ -1116,6 +1114,7 @@ void page_add_file_rmap(struct page *page)
*/
void page_remove_rmap(struct page *page)
{
+ struct address_space *mapping = page_mapping(page);
bool anon = PageAnon(page);
bool locked;
unsigned long flags;
@@ -1138,8 +1137,19 @@ void page_remove_rmap(struct page *page)
* this if the page is anon, so about to be freed; but perhaps
* not if it's in swapcache - there might be another pte slot
* containing the swap entry, but page not yet written to swap.
+ *
+ * And we can skip it on file pages, so long as the filesystem
+ * participates in dirty tracking; but need to catch shm and tmpfs
+ * and ramfs pages which have been modified since creation by read
+ * fault.
+ *
+ * Note that mapping must be decided above, before decrementing
+ * mapcount (which luckily provides a barrier): once page is unmapped,
+ * it could be truncated and page->mapping reset to NULL at any moment.
+ * Note also that we are relying on page_mapping(page) to set mapping
+ * to &swapper_space when PageSwapCache(page).
*/
- if ((!anon || PageSwapCache(page)) &&
+ if (mapping && !mapping_cap_account_dirty(mapping) &&
page_test_and_clear_dirty(page_to_pfn(page), 1))
set_page_dirty(page);
/*