1 files changed, 43 insertions, 45 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 8d9b19f..59ffcdb 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -761,23 +761,22 @@ int __set_page_dirty_nobuffers(struct page *page)
 		struct address_space *mapping = page_mapping(page);
 		struct address_space *mapping2;
 
-		if (mapping) {
-			write_lock_irq(&mapping->tree_lock);
-			mapping2 = page_mapping(page);
-			if (mapping2) { /* Race with truncate? */
-				BUG_ON(mapping2 != mapping);
-				if (mapping_cap_account_dirty(mapping))
-					__inc_zone_page_state(page,
-								NR_FILE_DIRTY);
-				radix_tree_tag_set(&mapping->page_tree,
-					page_index(page), PAGECACHE_TAG_DIRTY);
-			}
-			write_unlock_irq(&mapping->tree_lock);
-			if (mapping->host) {
-				/* !PageAnon && !swapper_space */
-				__mark_inode_dirty(mapping->host,
-							I_DIRTY_PAGES);
-			}
+		if (!mapping)
+			return 1;
+
+		write_lock_irq(&mapping->tree_lock);
+		mapping2 = page_mapping(page);
+		if (mapping2) { /* Race with truncate? */
+			BUG_ON(mapping2 != mapping);
+			if (mapping_cap_account_dirty(mapping))
+				__inc_zone_page_state(page, NR_FILE_DIRTY);
+			radix_tree_tag_set(&mapping->page_tree,
+				page_index(page), PAGECACHE_TAG_DIRTY);
+		}
+		write_unlock_irq(&mapping->tree_lock);
+		if (mapping->host) {
+			/* !PageAnon && !swapper_space */
+			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 		}
 		return 1;
 	}
@@ -851,27 +850,26 @@ int test_clear_page_dirty(struct page *page)
 	struct address_space *mapping = page_mapping(page);
 	unsigned long flags;
 
-	if (mapping) {
-		write_lock_irqsave(&mapping->tree_lock, flags);
-		if (TestClearPageDirty(page)) {
-			radix_tree_tag_clear(&mapping->page_tree,
-						page_index(page),
-						PAGECACHE_TAG_DIRTY);
-			write_unlock_irqrestore(&mapping->tree_lock, flags);
-			/*
-			 * We can continue to use `mapping' here because the
-			 * page is locked, which pins the address_space
-			 */
-			if (mapping_cap_account_dirty(mapping)) {
-				page_mkclean(page);
-				dec_zone_page_state(page, NR_FILE_DIRTY);
-			}
-			return 1;
-		}
+	if (!mapping)
+		return TestClearPageDirty(page);
+
+	write_lock_irqsave(&mapping->tree_lock, flags);
+	if (TestClearPageDirty(page)) {
+		radix_tree_tag_clear(&mapping->page_tree,
+				page_index(page), PAGECACHE_TAG_DIRTY);
 		write_unlock_irqrestore(&mapping->tree_lock, flags);
-		return 0;
+		/*
+		 * We can continue to use `mapping' here because the
+		 * page is locked, which pins the address_space
+		 */
+		if (mapping_cap_account_dirty(mapping)) {
+			page_mkclean(page);
+			dec_zone_page_state(page, NR_FILE_DIRTY);
+		}
+		return 1;
 	}
-	return TestClearPageDirty(page);
+	write_unlock_irqrestore(&mapping->tree_lock, flags);
+	return 0;
 }
 EXPORT_SYMBOL(test_clear_page_dirty);
 
@@ -893,17 +891,17 @@ int clear_page_dirty_for_io(struct page *page)
 {
 	struct address_space *mapping = page_mapping(page);
 
-	if (mapping) {
-		if (TestClearPageDirty(page)) {
-			if (mapping_cap_account_dirty(mapping)) {
-				page_mkclean(page);
-				dec_zone_page_state(page, NR_FILE_DIRTY);
-			}
-			return 1;
+	if (!mapping)
+		return TestClearPageDirty(page);
+
+	if (TestClearPageDirty(page)) {
+		if (mapping_cap_account_dirty(mapping)) {
+			page_mkclean(page);
+			dec_zone_page_state(page, NR_FILE_DIRTY);
 		}
-		return 0;
+		return 1;
 	}
-	return TestClearPageDirty(page);
+	return 0;
 }
 EXPORT_SYMBOL(clear_page_dirty_for_io);