gfs2: use pagevec_lookup_range_tag()

We want only pages from given range in gfs2_write_cache_jdata().  Use
pagevec_lookup_range_tag() instead of pagevec_lookup_tag() and remove
unnecessary code.

Link: http://lkml.kernel.org/r/20171009151359.31984-9-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/gfs2/aops.c

@@ -280,22 +280,6 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 	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.
-			 */
-			ret = 1;
-			break;
-		}
-
 		*done_index = page->index;
 
 		lock_page(page);
@@ -413,8 +397,8 @@ retry:
 		tag_pages_for_writeback(mapping, index, end);
 	done_index = index;
 	while (!done && (index <= end)) {
-		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;