From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0045.outbound.protection.outlook.com ([104.47.42.45]:15136 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751570AbdBCAUO (ORCPT ); Thu, 2 Feb 2017 19:20:14 -0500 From: Bart Van Assche To: "snitzer@redhat.com" CC: "hch@lst.de" , "linux-block@vger.kernel.org" , "axboe@fb.com" Subject: Re: split scsi passthrough fields out of struct request V2 Date: Fri, 3 Feb 2017 00:20:07 +0000 Message-ID: <1486081190.2816.26.camel@sandisk.com> References: <9198f024-9d55-3a28-9f77-ecbca42873b5@kernel.dk> <1485967586.2560.1.camel@sandisk.com> <7e963480-edf9-5687-25f3-83890373a26f@kernel.dk> <1485986472.2560.14.camel@sandisk.com> <1486056424.2816.4.camel@sandisk.com> <20170202183334.GB26910@redhat.com> <1486060991.2816.8.camel@sandisk.com> <20170202191330.GA27107@redhat.com> <1486064795.2816.14.camel@sandisk.com> <20170202210434.GA27548@redhat.com> <20170202211014.GA27604@redhat.com> In-Reply-To: <20170202211014.GA27604@redhat.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Thu, 2017-02-02 at 16:10 -0500, Mike Snitzer wrote: > Care to try moving the dm_get(md) at the end of dm_start_request() to > the beginning of dm_start_request() and report back on whether it helps > at all? Hello Mike, Sorry but I don't see how that could make a difference. While we are at it: since dm_start_request() calls dm_get() and since rq_completed() calls dm_put(), calls to these two functions should always be paired. There is only one dm_start_request() call in the dm-mq code, namely the one in dm_mq_queue_rq(). However, if map_request() returns DM_MAPIO_REQUEUE then rq_completed() is called twice: a first time by dm_requeue_original_request() and a second time by the dm_mq_queue_rq(). Do you agree with this? Thanks, Bart.=