[PATCH 2/7] mm: Refactor truncate_complete_page()

[Jan Kara <jack@suse.cz>]

Move call of delete_from_page_cache() and page->mapping check out of
truncate_complete_page() into the single caller - truncate_inode_page().
Also move page_mapped() check into truncate_complete_page(). That way it
will be easier to batch operations. Also rename truncate_complete_page()
to truncate_cleanup_page().

Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/truncate.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/mm/truncate.c b/mm/truncate.c
index 2330223841fb..383a530d511e 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -134,11 +134,17 @@ void do_invalidatepage(struct page *page, unsigned int offset,
  * its lock, b) when a concurrent invalidate_mapping_pages got there first and
  * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
  */
-static int
-truncate_complete_page(struct address_space *mapping, struct page *page)
+static void
+truncate_cleanup_page(struct address_space *mapping, struct page *page)
 {
-	if (page->mapping != mapping)
-		return -EIO;
+	if (page_mapped(page)) {
+		loff_t holelen;
+
+		holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
+		unmap_mapping_range(mapping,
+				   (loff_t)page->index << PAGE_SHIFT,
+				   holelen, 0);
+	}
 
 	if (page_has_private(page))
 		do_invalidatepage(page, 0, PAGE_SIZE);
@@ -150,8 +156,6 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
 	 */
 	cancel_dirty_page(page);
 	ClearPageMappedToDisk(page);
-	delete_from_page_cache(page);
-	return 0;
 }
 
 /*
@@ -180,16 +184,14 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
 
 int truncate_inode_page(struct address_space *mapping, struct page *page)
 {
-	loff_t holelen;
 	VM_BUG_ON_PAGE(PageTail(page), page);
 
-	holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
-	if (page_mapped(page)) {
-		unmap_mapping_range(mapping,
-				   (loff_t)page->index << PAGE_SHIFT,
-				   holelen, 0);
-	}
-	return truncate_complete_page(mapping, page);
+	if (page->mapping != mapping)
+		return -EIO;
+
+	truncate_cleanup_page(mapping, page);
+	delete_from_page_cache(page);
+	return 0;
 }
 
 /*
-- 
2.12.3

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