From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:52433 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751362AbcGMQVg (ORCPT ); Wed, 13 Jul 2016 12:21:36 -0400 Subject: Re: [PATCH] block: Fix front merge check To: Damien Le Moal , , , References: <1468387413-2754-1-git-send-email-damien.lemoal@hgst.com> From: Jens Axboe Message-ID: <57866A2B.5000403@fb.com> Date: Wed, 13 Jul 2016 09:19:55 -0700 MIME-Version: 1.0 In-Reply-To: <1468387413-2754-1-git-send-email-damien.lemoal@hgst.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On 07/12/2016 10:23 PM, Damien Le Moal wrote: > For a front merge, the maximum number of sectors of the > request must be checked against the front merge BIO sector, > not the current sector of the request. Why does this matter? The merging should only happen before we start the request, hence rq pos and first bio should be one and the same. -- Jens Axboe