Merge remote-tracking branch 'kernelorg/linux-3.0.y' into 3_0_64

Conflicts:
	arch/arm/Kconfig
	arch/arm/include/asm/hwcap.h
	arch/arm/kernel/smp.c
	arch/arm/plat-samsung/adc.c
	drivers/gpu/drm/i915/i915_reg.h
	drivers/gpu/drm/i915/intel_drv.h
	drivers/mmc/core/sd.c
	drivers/net/tun.c
	drivers/net/usb/usbnet.c
	drivers/regulator/max8997.c
	drivers/usb/core/hub.c
	drivers/usb/host/xhci.h
	drivers/usb/serial/qcserial.c
	fs/jbd2/transaction.c
	include/linux/migrate.h
	kernel/sys.c
	kernel/time/timekeeping.c
	lib/genalloc.c
	mm/memory-failure.c
	mm/memory_hotplug.c
	mm/mempolicy.c
	mm/page_alloc.c
	mm/vmalloc.c
	mm/vmscan.c
	mm/vmstat.c
	scripts/Kbuild.include

Change-Id: I91e2d85c07320c7ccfc04cf98a448e89bed6ade6

1 files changed, 16 insertions, 5 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 23295f6..30e44cb 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -57,6 +57,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/migrate.h>
 #include <linux/hugetlb.h>
+#include <linux/backing-dev.h>
 
 #include <asm/tlbflush.h>
 
@@ -936,11 +937,8 @@ 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;
@@ -1121,6 +1119,8 @@ void page_add_file_rmap(struct page *page)
  */
 void page_remove_rmap(struct page *page)
 {
+	struct address_space *mapping = page_mapping(page);
+
 	/* page still mapped by someone else? */
 	if (!atomic_add_negative(-1, &page->_mapcount))
 		return;
@@ -1131,8 +1131,19 @@ 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 ((!PageAnon(page) || PageSwapCache(page)) &&
+	if (mapping && !mapping_cap_account_dirty(mapping) &&
 	    page_test_and_clear_dirty(page_to_pfn(page), 1))
 		set_page_dirty(page);
 	/*