1 files changed, 27 insertions, 59 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index ff24c9d8311..6f4335238e3 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1541,16 +1541,6 @@ pause:
 		bdi_start_background_writeback(bdi);
 }
 
-void set_page_dirty_balance(struct page *page)
-{
-	if (set_page_dirty(page)) {
-		struct address_space *mapping = page_mapping(page);
-
-		if (mapping)
-			balance_dirty_pages_ratelimited(mapping);
-	}
-}
-
 static DEFINE_PER_CPU(int, bdp_ratelimits);
 
 /*
@@ -2116,23 +2106,6 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 EXPORT_SYMBOL(account_page_dirtied);
 
 /*
- * Helper function for set_page_writeback family.
- *
- * The caller must hold mem_cgroup_begin/end_update_page_stat() lock
- * while calling this function.
- * See test_set_page_writeback for example.
- *
- * NOTE: Unlike account_page_dirtied this does not rely on being atomic
- * wrt interrupts.
- */
-void account_page_writeback(struct page *page)
-{
-	mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
-	inc_zone_page_state(page, NR_WRITEBACK);
-}
-EXPORT_SYMBOL(account_page_writeback);
-
-/*
  * For address_spaces which do not use buffers.  Just tag the page as dirty in
  * its radix tree.
  *
@@ -2140,32 +2113,25 @@ EXPORT_SYMBOL(account_page_writeback);
  * page dirty in that case, but not all the buffers.  This is a "bottom-up"
  * dirtying, whereas __set_page_dirty_buffers() is a "top-down" dirtying.
  *
- * Most callers have locked the page, which pins the address_space in memory.
- * But zap_pte_range() does not lock the page, however in that case the
- * mapping is pinned by the vma's ->vm_file reference.
- *
- * We take care to handle the case where the page was truncated from the
- * mapping by re-checking page_mapping() inside tree_lock.
+ * The caller must ensure this doesn't race with truncation.  Most will simply
+ * hold the page lock, but e.g. zap_pte_range() calls with the page mapped and
+ * the pte lock held, which also locks out truncation.
  */
 int __set_page_dirty_nobuffers(struct page *page)
 {
 	if (!TestSetPageDirty(page)) {
 		struct address_space *mapping = page_mapping(page);
-		struct address_space *mapping2;
 		unsigned long flags;
 
 		if (!mapping)
 			return 1;
 
 		spin_lock_irqsave(&mapping->tree_lock, flags);
-		mapping2 = page_mapping(page);
-		if (mapping2) { /* Race with truncate? */
-			BUG_ON(mapping2 != mapping);
-			WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
-			account_page_dirtied(page, mapping);
-			radix_tree_tag_set(&mapping->page_tree,
-				page_index(page), PAGECACHE_TAG_DIRTY);
-		}
+		BUG_ON(page_mapping(page) != mapping);
+		WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
+		account_page_dirtied(page, mapping);
+		radix_tree_tag_set(&mapping->page_tree, page_index(page),
+				   PAGECACHE_TAG_DIRTY);
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
 		if (mapping->host) {
 			/* !PageAnon && !swapper_space */
@@ -2322,12 +2288,10 @@ int clear_page_dirty_for_io(struct page *page)
 		/*
 		 * We carefully synchronise fault handlers against
 		 * installing a dirty pte and marking the page dirty
-		 * at this point. We do this by having them hold the
-		 * page lock at some point after installing their
-		 * pte, but before marking the page dirty.
-		 * Pages are always locked coming in here, so we get
-		 * the desired exclusion. See mm/memory.c:do_wp_page()
-		 * for more comments.
+		 * at this point.  We do this by having them hold the
+		 * page lock while dirtying the page, and pages are
+		 * always locked coming in here, so we get the desired
+		 * exclusion.
 		 */
 		if (TestClearPageDirty(page)) {
 			dec_zone_page_state(page, NR_FILE_DIRTY);
@@ -2344,11 +2308,12 @@ EXPORT_SYMBOL(clear_page_dirty_for_io);
 int test_clear_page_writeback(struct page *page)
 {
 	struct address_space *mapping = page_mapping(page);
-	int ret;
-	bool locked;
 	unsigned long memcg_flags;
+	struct mem_cgroup *memcg;
+	bool locked;
+	int ret;
 
-	mem_cgroup_begin_update_page_stat(page, &locked, &memcg_flags);
+	memcg = mem_cgroup_begin_page_stat(page, &locked, &memcg_flags);
 	if (mapping) {
 		struct backing_dev_info *bdi = mapping->backing_dev_info;
 		unsigned long flags;
@@ -2369,22 +2334,23 @@ int test_clear_page_writeback(struct page *page)
 		ret = TestClearPageWriteback(page);
 	}
 	if (ret) {
-		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
+		mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
 		dec_zone_page_state(page, NR_WRITEBACK);
 		inc_zone_page_state(page, NR_WRITTEN);
 	}
-	mem_cgroup_end_update_page_stat(page, &locked, &memcg_flags);
+	mem_cgroup_end_page_stat(memcg, &locked, &memcg_flags);
 	return ret;
 }
 
 int __test_set_page_writeback(struct page *page, bool keep_write)
 {
 	struct address_space *mapping = page_mapping(page);
-	int ret;
-	bool locked;
 	unsigned long memcg_flags;
+	struct mem_cgroup *memcg;
+	bool locked;
+	int ret;
 
-	mem_cgroup_begin_update_page_stat(page, &locked, &memcg_flags);
+	memcg = mem_cgroup_begin_page_stat(page, &locked, &memcg_flags);
 	if (mapping) {
 		struct backing_dev_info *bdi = mapping->backing_dev_info;
 		unsigned long flags;
@@ -2410,9 +2376,11 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
 	} else {
 		ret = TestSetPageWriteback(page);
 	}
-	if (!ret)
-		account_page_writeback(page);
-	mem_cgroup_end_update_page_stat(page, &locked, &memcg_flags);
+	if (!ret) {
+		mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+		inc_zone_page_state(page, NR_WRITEBACK);
+	}
+	mem_cgroup_end_page_stat(memcg, &locked, &memcg_flags);
 	return ret;
 
 }