From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 938A3C32771 for ; Mon, 13 Jan 2020 03:30:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 66059206D6 for ; Mon, 13 Jan 2020 03:30:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733124AbgAMDa1 (ORCPT ); Sun, 12 Jan 2020 22:30:27 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:42840 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732961AbgAMDa1 (ORCPT ); Sun, 12 Jan 2020 22:30:27 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 2566941A5205CB78BBAE; Mon, 13 Jan 2020 11:30:25 +0800 (CST) Received: from [127.0.0.1] (10.74.219.194) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.439.0; Mon, 13 Jan 2020 11:30:16 +0800 Subject: Re: Failed to disable WCE for a SATA disk To: "axboe@kernel.dk" , Tejun Heo , "Martin K. Petersen" , Bart Van Assche References: CC: "linux-scsi@vger.kernel.org" , , Linuxarm , John Garry From: "chenxiang (M)" Message-ID: Date: Mon, 13 Jan 2020 11:30:15 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.74.219.194] X-CFilter-Loop: Reflected Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi, 在 2019/12/11 11:21, chenxiang (M) 写道: > Hi, > > I encounter a issue related to libata and libsas. For hisi_sas driver, > it uses libsas. When disable WCE with tool sdparm (sdparm --clear=WCE > /dev/sda) for a SATA disk, > it fails with error info from hardware (the error info indicates that > the length of transfer data is conflicted with the direction of data, > the length is 0 but > the data of direction is from host to device). > > I check the process: When disable WCE, it sends pasthrough IO with > sg_io , req->__data_len is not 0, and scsi_cmd->sc_data_direction = > DMA_TO_DEVICE. > But for the command (MODE_SELECT), qc->tf.protocol is set 0 (not > ATA_PROT_DMA) in ->queuecommand() > ->ata_sas_queuecmd()->ata_scsi_translate()->ata_scsi_mod_select_xlat()->ata_mselect_caching(), > so it doesn't dma map ata sg in function ata_qc_issue(). While in > function sas_ata_qc_issue()，it calcutes the length with the total sum > of sg_dma_len(sg), as for the > command it doesn't dma map ata sg, so the length is 0. > > Do we need to dma map ata sg for the command? Or is it really we need > the data for the command MODE_SELECT? Does anyone have idea about it ? > > Thanks, > Shawn > > > > > . >