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 C4DB8C67871 for ; Thu, 27 Oct 2022 08:11:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234545AbiJ0IL3 (ORCPT ); Thu, 27 Oct 2022 04:11:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234892AbiJ0ILO (ORCPT ); Thu, 27 Oct 2022 04:11:14 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DFD65071F; Thu, 27 Oct 2022 01:11:12 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 2A5CF228C4; Thu, 27 Oct 2022 08:11:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1666858271; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Dav8/trZpl1RqcozNrS2x/LCkcv0lpz2Ke14qSzjIvQ=; b=JBW1kgDneyAMd+g1LB1A+RcN3vmn8b8CWCMMAhe6BrvgQSnDIfD8OJ39gzMHt9dM4a4ZQ4 6GkVNNILTCTakhg04j4gYbtvgy36aJe6QLqbaPCUfJM5vr/3QMcU8BSiRLb6/Mu/nrJB8b Lcx5j2RyxLY8rmXg5gYD2QHDimGQj/8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1666858271; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Dav8/trZpl1RqcozNrS2x/LCkcv0lpz2Ke14qSzjIvQ=; b=6LRkxk+HVFMPqwGqpfxen+YYBGDCmXopA7ll9fhQZlt5oe0K4Ue4CZmoRRyLBs7zeWdmea 6DrQgWa5s9SAAHDA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 4121A134CA; Thu, 27 Oct 2022 08:11:10 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id HnrtDB49WmPoOAAAMHmgww (envelope-from ); Thu, 27 Oct 2022 08:11:10 +0000 Message-ID: Date: Thu, 27 Oct 2022 10:11:09 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH RFC v3 16/22] ata: libata-scsi: Allocate sdev early in port probe Content-Language: en-US To: Damien Le Moal , John Garry , axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com, jinpu.wang@cloud.ionos.com, bvanassche@acm.org, hch@lst.de, ming.lei@redhat.com, niklas.cassel@wdc.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linuxarm@huawei.com References: <1666693096-180008-1-git-send-email-john.garry@huawei.com> <1666693096-180008-17-git-send-email-john.garry@huawei.com> <6c0a4a75-786a-c946-57f2-c511bd765bcc@opensource.wdc.com> From: Hannes Reinecke In-Reply-To: <6c0a4a75-786a-c946-57f2-c511bd765bcc@opensource.wdc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/27/22 03:34, Damien Le Moal wrote: > On 10/25/22 19:18, John Garry wrote: >> Currently the per-ata device sdev is allocated as part of the scsi target >> scan, which is after the ata port probe. >> >> However it is useful to have the sdev available in the port probe. As an >> example of an advantage, if the request queue is available in the probe >> (which it would be if the sdev is available), then it is possible to use >> a SCSI cmnd for ATA internal commands. The benefit of this is then we can >> put the ATA qc structure in the SCSI cmnd private data. It will also be >> useful if we want to send ATA internal commands as requests. >> >> Export scsi_target_reap() so that it can be used to put the extra >> reference we get when allocating the sdev. >> >> Signed-off-by: John Garry >> --- >> drivers/ata/libata-eh.c | 1 + >> drivers/ata/libata-scsi.c | 23 +++++++++-------------- >> drivers/scsi/scsi_scan.c | 1 + >> 3 files changed, 11 insertions(+), 14 deletions(-) >> >> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c >> index 08e11bc312c2..1ed5b1b64792 100644 >> --- a/drivers/ata/libata-eh.c >> +++ b/drivers/ata/libata-eh.c >> @@ -3446,6 +3446,7 @@ static int ata_eh_schedule_probe(struct ata_device *dev) >> >> ata_eh_detach_dev(dev); >> ata_dev_init(dev); >> + ata_scsi_setup_sdev(dev); >> ehc->did_probe_mask |= (1 << dev->devno); >> ehc->i.action |= ATA_EH_RESET; >> ehc->saved_xfer_mode[dev->devno] = 0; >> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c >> index efdba852e363..476e0ef4bd29 100644 >> --- a/drivers/ata/libata-scsi.c >> +++ b/drivers/ata/libata-scsi.c >> @@ -1109,7 +1109,12 @@ int ata_scsi_dev_config(struct scsi_device *sdev, struct ata_device *dev) >> if (dev->flags & ATA_DFLAG_TRUSTED) >> sdev->security_supported = 1; >> >> - dev->sdev = sdev; >> + /* >> + * Put extra reference which we get when allocating the starget >> + * initially >> + */ >> + scsi_target_reap(scsi_target(sdev)); >> + >> return 0; >> } >> >> @@ -4289,26 +4294,16 @@ void ata_scsi_scan_host(struct ata_port *ap, int sync) >> repeat: >> ata_for_each_link(link, ap, EDGE) { >> ata_for_each_dev(dev, link, ENABLED) { >> - struct scsi_device *sdev; >> + struct Scsi_Host *shost = ap->scsi_host; >> int channel = 0, id = 0; >> >> - if (dev->sdev) >> - continue; >> - >> if (ata_is_host_link(link)) >> id = dev->devno; >> else >> channel = link->pmp; >> >> - sdev = __scsi_add_device(ap->scsi_host, channel, id, 0, >> - NULL); >> - if (!IS_ERR(sdev)) { >> - dev->sdev = sdev; >> - ata_scsi_assign_ofnode(dev, ap); > > Is there something equivalent to what this function does inside > scsi_scan_target() ? I had a quick look but did not see anything... > Typically, the SCSI layer has two ways of scanning. One it the old-style serial scanning (originating in the old SCSI parallel model): The scanning code will blindly scan _all_ devices up to max_luns, and attach every device for which the scanning code returns 'OK'. The other one is to issue REPORT_LUNS and scan all LUNs returned there. Mapped to libata we would need to figure out a stable SCSI enumeration, given that we have PMP and slave devices to content with. To my knowledge we have ATA ports, each can have either a 'master' and 'slave' device, _or_ it be a PMP port when it can support up to 16 devices, right? Point being, master/slave and PMP are exclusive, right? So we can make the master as LUN 0, and the slave as LUN 1. And for PMP we can use each PMP address as LUN + 1, and keeping the actual device as LUN 0. I think we can figure out whether it's a master/slave device setup upfront, so we should be able to set max_luns to '2' for these devices. For PMP-capable (or devices which _might_ be PMP capable), we could emulate the REPORT LUNS command, mapping on the PMP mechanism to figure out which devices are connected. Would that work? Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew Myers, Andrew McDonald, Martje Boudien Moerman