[PATCHv6 10/37] filemap: handle huge pages in filemap_fdatawait_range()

["Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>]

We writeback whole huge page a time.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 mm/filemap.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mm/filemap.c b/mm/filemap.c
index 4e398d5e4134..f5cd654b3662 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -405,9 +405,14 @@ static int __filemap_fdatawait_range(struct address_space *mapping,
 			if (page->index > end)
 				continue;
 
+			page = compound_head(page);
 			wait_on_page_writeback(page);
 			if (TestClearPageError(page))
 				ret = -EIO;
+			if (PageTransHuge(page)) {
+				index = page->index + HPAGE_PMD_NR;
+				i += index - pvec.pages[i]->index - 1;
+			}
 		}
 		pagevec_release(&pvec);
 		cond_resched();
-- 
2.11.0