mm: use pagevec_lookup_range_tag() in __filemap_fdatawait_range()

Use pagevec_lookup_range_tag() in __filemap_fdatawait_range() as it is
interested only in pages from given range.  Remove unnecessary code
resulting from this.

Link: http://lkml.kernel.org/r/20171009151359.31984-11-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index cf74d0dacc6a..229481d258bc 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -420,19 +420,17 @@ static void __filemap_fdatawait_range(struct address_space *mapping,
                 return;
 
         pagevec_init(&pvec, 0);
-        while ((index <= end) &&
-                        (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
-                        PAGECACHE_TAG_WRITEBACK,
-                        min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) {
+        while (index <= end) {
                 unsigned i;
 
+                nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index,
+                                end, PAGECACHE_TAG_WRITEBACK, PAGEVEC_SIZE);
+                if (!nr_pages)
+                        break;
+
                 for (i = 0; i < nr_pages; i++) {
                         struct page *page = pvec.pages[i];
 
-                        /* until radix tree lookup accepts end_index */
-                        if (page->index > end)
-                                continue;
-
                         wait_on_page_writeback(page);
                         ClearPageError(page);
                 }