Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752306AbdHHIqi (ORCPT ); Tue, 8 Aug 2017 04:46:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39906 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752278AbdHHIqg (ORCPT ); Tue, 8 Aug 2017 04:46:36 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 531914E047 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=ming.lei@redhat.com From: Ming Lei To: Jens Axboe , Christoph Hellwig , Huang Ying , Andrew Morton , Alexander Viro Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Ming Lei Subject: [PATCH v3 02/49] block: loop: comment on direct access to bvec table Date: Tue, 8 Aug 2017 16:45:01 +0800 Message-Id: <20170808084548.18963-3-ming.lei@redhat.com> In-Reply-To: <20170808084548.18963-1-ming.lei@redhat.com> References: <20170808084548.18963-1-ming.lei@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 08 Aug 2017 08:46:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 773 Lines: 23 Signed-off-by: Ming Lei --- drivers/block/loop.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index ef8334949b42..58df9ed70328 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -487,6 +487,11 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, /* nomerge for loop request queue */ WARN_ON(cmd->rq->bio != cmd->rq->biotail); + /* + * For multipage bvec support, it is safe to pass the bvec + * table to iov iterator, because iov iter still uses bvec + * iter helpers to travese bvec. + */ bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); iov_iter_bvec(&iter, ITER_BVEC | rw, bvec, bio_segments(bio), blk_rq_bytes(cmd->rq)); -- 2.9.4