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([2a01:4a0:2e:ffff:ffff:ffff:ffff:ffff]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48722fa8dc6sm38717085e9.1.2026.03.26.03.19.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 26 Mar 2026 03:19:11 -0700 (PDT) Message-ID: Date: Thu, 26 Mar 2026 11:19:10 +0100 Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/13] scsi: Core ALUA driver To: John Garry , Benjamin Marzinski Cc: martin.petersen@oracle.com, james.bottomley@hansenpartnership.com, jmeneghi@redhat.com, linux-scsi@vger.kernel.org, michael.christie@oracle.com, snitzer@kernel.org, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260317120703.3702387-1-john.g.garry@oracle.com> <10aab639-2fe8-47b7-b821-12d21b6af874@oracle.com> <43ca92bc-af38-4833-841c-421997ed90fe@oracle.com> <2f84e35f-3574-45e8-9567-4edcfdbe5a45@oracle.com> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <2f84e35f-3574-45e8-9567-4edcfdbe5a45@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 3/24/26 16:12, John Garry wrote: > On 24/03/2026 13:58, Benjamin Marzinski wrote: >>>> If it allowed device handlers to get attached, these two >>>> developement efforts (native scsi multipath and refactoring the alua >>>> support) could go on in parallel. >>>> >>>> Or am I missing something here? >>> It just seems to be about this DH stuff is that there is bad history >>> there >>> and no more users are wanted. >> Just to be clear, if the idea was that the Native Multipath code >> shouldn't use include/scsi/scsi_dh.h, I completely agree with that. But >> I don't see why it can't make use of the results of the existing >> implicit ALUA support, since IIUC it doesn't need the scsi_dh interface >> to do that. > > We would need something like the following to ensure that DH ALUA is > present to update sdev access_state: > > @@ -80,6 +80,7 @@ config SCSI_MULTIPATH >         bool "SCSI multipath support" >         depends on SCSI_MOD >         select LIBMULTIPATH > +       select SCSI_DH_ALUA >         help >           This option enables support for native SCSI multipath support > for >           SCSI host. > > And that is even enough, as Kconfigs should only specify build > requirements. > > We really should be also calling something like scsi_dh_attach() for > scsi multipath to ensure that DH is attached (and running to update > sdev->access_state). > > And I am not sure how the dh alua module is even autoloaded. I think > that on my ubuntu machine the multipath-tools.service does it - > something like this would not be nice for native SCSI multipath support. > Gnaa. But then we don't need this patchset at all. Main point was that we _do not_ need to hook into scsi dh for implicit ALUA. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.com +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich