ceph: use release_pages() directly

release_pages() has been available to modules since Oct, 2010,
when commit 0be8557b ("fuse: use release_pages()") added
EXPORT_SYMBOL(release_pages). However, this ceph code was still
using a workaround.

Remove the workaround, and call release_pages() directly.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/addr.c

@@ -684,23 +684,6 @@ static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 	return err;
 }
 
-/*
- * lame release_pages helper.  release_pages() isn't exported to
- * modules.
- */
-static void ceph_release_pages(struct page **pages, int num)
-{
-	struct pagevec pvec;
-	int i;
-
-	pagevec_init(&pvec);
-	for (i = 0; i < num; i++) {
-		if (pagevec_add(&pvec, pages[i]) == 0)
-			pagevec_release(&pvec);
-	}
-	pagevec_release(&pvec);
-}
-
 /*
  * async writeback completion handler.
  *
@@ -776,7 +759,7 @@ static void writepages_finish(struct ceph_osd_request *req)
 		dout("writepages_finish %p wrote %llu bytes cleaned %d pages\n",
 		     inode, osd_data->length, rc >= 0 ? num_pages : 0);
 
-		ceph_release_pages(osd_data->pages, num_pages);
+		release_pages(osd_data->pages, num_pages);
 	}
 
 	ceph_put_wrbuffer_cap_refs(ci, total_pages, snapc);