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([2a01:4a0:2e:ffff:ffff:ffff:ffff:ffff]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439dae46353sm42155639f8f.33.2026.03.10.06.27.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Mar 2026 06:27:10 -0700 (PDT) Message-ID: Date: Tue, 10 Mar 2026 14:27:09 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6/8] scsi: scsi-multipath: Maintain sdev->access_state To: John Garry , hch@lst.de, kbusch@kernel.org, martin.petersen@oracle.com, james.bottomley@hansenpartnership.com, bmarzins@redhat.com Cc: jmeneghi@redhat.com, linux-nvme@lists.infradead.org, sagi@grimberg.me, axboe@fb.com, linux-scsi@vger.kernel.org, michael.christie@oracle.com, snitzer@kernel.org, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org, nilay@linux.ibm.com References: <20260310114925.1222263-1-john.g.garry@oracle.com> <20260310114925.1222263-7-john.g.garry@oracle.com> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <20260310114925.1222263-7-john.g.garry@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 3/10/26 12:49, John Garry wrote: > Now that ALUA is supported, we can maintain sdev->access_state. > > However, preferred_path is still not maintained as that that is related > to transitioning state and we do not yet support that (for SCSI > multipath). > There is an issue with the preferred path in general, namely that it overlays the ALUA states (ie you can have 'acive/non-optimized' _and_ the preferred path bit set). So it only makes sense for explicit ALUA as then the preferred path bit gives us an indicator that we might / should switch paths. If we restrict ourselves to implicit ALUA (which I'm advocating anyway for scsi-multipath) the preferred path becomes rather pointless as we cannot influence path selection at all. 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