mm: use pagevec_lookup_range_tag() in write_cache_pages()

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

Link: http://lkml.kernel.org/r/20171009151359.31984-12-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, 2 insertions, 18 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 768fe4e37e6a..460fc022cbc8 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2196,30 +2196,14 @@ retry:
         while (!done && (index <= end)) {
                 int i;
 
-                nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
-                              min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
+                nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
+                                tag, PAGEVEC_SIZE);
                 if (nr_pages == 0)
                         break;
 
                 for (i = 0; i < nr_pages; i++) {
                         struct page *page = pvec.pages[i];
 
-                        /*
-                         * At this point, the page may be truncated or
-                         * invalidated (changing page->mapping to NULL), or
-                         * even swizzled back from swapper_space to tmpfs file
-                         * mapping. However, page->index will not change
-                         * because we have a reference on the page.
-                         */
-                        if (page->index > end) {
-                                /*
-                                 * can't be range_cyclic (1st pass) because
-                                 * end == -1 in that case.
-                                 */
-                                done = 1;
-                                break;
-                        }
-
                         done_index = page->index;
 
                         lock_page(page);