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>

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 768fe4e37e6aedcb1b5f98633b8c5ad65aab1db3..460fc022cbc8a11e0c3ec62f3647aa2dc4640a6e 100644 (file)
--- 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);