mm: refactor truncate_complete_page()

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().

Link: http://lkml.kernel.org/r/20171010151937.26984-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files 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;
 }
 
 /*