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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC459C77B7F for ; Sat, 6 May 2023 09:57:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231226AbjEFJ5V (ORCPT ); Sat, 6 May 2023 05:57:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230000AbjEFJ5S (ORCPT ); Sat, 6 May 2023 05:57:18 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2EFD946AA; Sat, 6 May 2023 02:57:16 -0700 (PDT) Received: from dggpemm500012.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4QD2ws0ZtNzsRBP; Sat, 6 May 2023 17:55:25 +0800 (CST) Received: from [10.67.101.126] (10.67.101.126) by dggpemm500012.china.huawei.com (7.185.36.89) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Sat, 6 May 2023 17:57:13 +0800 Message-ID: Date: Sat, 6 May 2023 17:57:13 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.1 Subject: Re: [PATCH v2] ata: libata-scsi: Fix get identity data failed Content-Language: en-CA To: John Garry , Damien Le Moal , , , CC: , , , , References: <20230505025712.19438-1-yangxingui@huawei.com> <291f1d97-9195-45ac-8e12-058f5c797277@kernel.org> <1b703656-e966-63f8-19dd-33e4e9914676@huawei.com> From: yangxingui In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.101.126] X-ClientProxiedBy: dggpemm100015.china.huawei.com (7.185.36.61) To dggpemm500012.china.huawei.com (7.185.36.89) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/5/5 17:51, John Garry wrote: > On 05/05/2023 10:14, yangxingui wrote: >>> hmmm... is it really acceptable that libata is referencing libsas? I >>> didn't think that it would be. libsas uses libata, not the other way >>> around. >> Yeah, I didn't expect that either. Is there any other way? If so, is >> patch v1 OK? > > I still think that we can do better than v1. OK > >>> >>>>>   #include >>>>>   #include >>>>>   #include >>>>> @@ -2745,10 +2746,17 @@ static struct ata_device >>>>> *__ata_scsi_find_dev(struct ata_port *ap, >>>>>    *    Associated ATA device, or %NULL if not found. >>>>>    */ >>>>>   struct ata_device * >>>>> -ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device >>>>> *scsidev) >>>> Why drop the const ? >>>> >>>>> +ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev) >>>>>   { >>>>> -    struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev); >>>>> +    struct ata_device *dev; >>>>> + >>>>> +    if (ap->flags & ATA_FLAG_SAS_HOST) { >>> >>> And this is SAS host. Not necessarily libsas (even though with ipr >>> libata usage gone, it would be the only user). >> Add a new flag only for libsas? > > No, because of previous reason. > > Please remind me - at what point do we error within ata_scsi_find_dev() > and return NULL for a libsas host? The scsi_host_template filled by libsas and call ata_scsi_find_dev() has this problem. After sas_change_queue_depth() is fixed, only sas_ioctl() has this problem now. > > Note: it would be good to include that commit message for future reference. > > Maybe we could add a method to ata_port_operations to do this lookup. I > assume that is abusing ata_port_operations purpose, since it's mostly > for HW methods. > > Or do we actually use sdev->hostdata for libata or libsas? If not, maybe > we could store the struct ata_device pointer there. Well, it might be a way. Thanks, Xingui . > > I'm just thinking out loud now... > > Thanks, > John > > > .