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 84123C32771 for ; Wed, 21 Sep 2022 08:24:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231343AbiIUIYm (ORCPT ); Wed, 21 Sep 2022 04:24:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229750AbiIUIYJ (ORCPT ); Wed, 21 Sep 2022 04:24:09 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97EFB54C82; Wed, 21 Sep 2022 01:24:07 -0700 (PDT) Received: from fraeml736-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4MXWd117pLz688JQ; Wed, 21 Sep 2022 16:23:01 +0800 (CST) Received: from lhrpeml500003.china.huawei.com (7.191.162.67) by fraeml736-chm.china.huawei.com (10.206.15.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 21 Sep 2022 10:24:04 +0200 Received: from [10.195.245.235] (10.195.245.235) by lhrpeml500003.china.huawei.com (7.191.162.67) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 21 Sep 2022 09:24:03 +0100 Message-ID: <0ae5000d-8e9a-da0f-b470-9f87f1b5e290@huawei.com> Date: Wed, 21 Sep 2022 09:24:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH RFC 0/6] libata/scsi/libsas: Allocate SCSI device earlier for ata port probe To: Damien Le Moal , , , , CC: , , , References: <1663669630-21333-1-git-send-email-john.garry@huawei.com> <40b9e090-5ba3-1191-4fe9-80467284ae72@opensource.wdc.com> From: John Garry In-Reply-To: <40b9e090-5ba3-1191-4fe9-80467284ae72@opensource.wdc.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.195.245.235] X-ClientProxiedBy: lhrpeml100003.china.huawei.com (7.191.160.210) To lhrpeml500003.china.huawei.com (7.191.162.67) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/09/2022 05:04, Damien Le Moal wrote: > On 9/20/22 19:27, John Garry wrote: >> Currently for libata the SCSI device (sdev) associated with an ata_device >> is allocated when the port probe has completed. >> >> It's useful to have the SCSI device and its associated request queue >> available earlier for the port probe. Specifically if we have the >> request queue available, then we can: >> - Easily put ATA qc in SCSI cmnd priv data >> - Send ATA internal commands on SCSI device request queue for [0]. The >>    current solution there is to use the shost sdev request queue, which >>    isn't great. >> This series changes the ata port probe to alloc the sdev in the >> ata_device revalidation, and then just do a SCSI starget scan afterwards. >> >> Why an RFC? >> 1. IPR  driver needs to be fixed up - it does not use ATA EH port probe >>     Mail [1] needs following up > > Yes. If IPR could be converted to ata error_handler, a lot of code can > be simplified in libata too. Hmmm... yeah, it would be good to see progress there. > >> 2. SATA PMP support needs verification, but I don't have a setup > > Port multiplier behind a sas HBA will be challenging to setup :) > I can try, but I will need to open up one of my servers and hook a small > PMP box to one of the pm8001 plugs. I may have the cables for that... > Let me check. I was more thinking of just AHCI with a port multiplier. As for SAS controllers, I don't think it's something to be concerned about. For a start, I know for sure that hisi_sas HW does not support port multipliers, and I don't think that pm8001 does either. In addition, libsas does not even support it - I did see a series in the scsi list from years ago (to support it), but it did not progress. Thanks, John