From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] nvme: allow ANA support to be independent of native multipathing Date: Fri, 16 Nov 2018 10:14:58 +0100 Message-ID: <20181116091458.GA17267@lst.de> References: <1541657381-7452-1-git-send-email-lijie34@huawei.com> <2691abf6733f791fb16b86d96446440e4aaff99f.camel@suse.com> <20181112215323.GA7983@redhat.com> <20181113161838.GC9827@localhost.localdomain> <20181113180008.GA12513@redhat.com> <20181114053837.GA15086@redhat.com> <30cf7af7-8826-55bd-e39a-4f81ed032f6d@suse.de> <20181114174746.GA18526@redhat.com> <87c931e5-4ac9-1795-8d40-cc5541d3ebcf@suse.de> <20181115174605.GA19782@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181115174605.GA19782@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Mike Snitzer Cc: linux-nvme@lists.infradead.org, Hannes Reinecke , Keith Busch , Sagi Grimberg , hch@lst.de, axboe@kernel.dk, Martin Wilck , lijie , xose.vazquez@gmail.com, chengjike.cheng@huawei.com, shenhong09@huawei.com, dm-devel@redhat.com, wangzhoumengjian@huawei.com, christophe.varoqui@opensvc.com, bmarzins@redhat.com, sschremm@netapp.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: dm-devel.ids On Thu, Nov 15, 2018 at 12:46:05PM -0500, Mike Snitzer wrote: > Whether or not ANA is present is a choice of the target implementation; > the host (and whether it supports multipathing) has _zero_ influence on > this. If the target declares a path as 'inaccessible' the path _is_ > inaccessible to the host. As such, ANA support should be functional > even if native multipathing is not. > > Introduce ability to always re-read ANA log page as required due to ANA > error and make current ANA state available via sysfs -- even if native > multipathing is disabled on the host (e.g. nvme_core.multipath=N). The first part I could see, but I still want to make it conditional in some way as nvme is going into deeply embedded setups, and I don't want to carry the weight of the ANA code around for everyone. The second I fundamentally disagree with. And even if you found agreement it would have to be in a separate patch as it is a separate feature. From mboxrd@z Thu Jan 1 00:00:00 1970 From: hch@lst.de (Christoph Hellwig) Date: Fri, 16 Nov 2018 10:14:58 +0100 Subject: [PATCH] nvme: allow ANA support to be independent of native multipathing In-Reply-To: <20181115174605.GA19782@redhat.com> References: <1541657381-7452-1-git-send-email-lijie34@huawei.com> <2691abf6733f791fb16b86d96446440e4aaff99f.camel@suse.com> <20181112215323.GA7983@redhat.com> <20181113161838.GC9827@localhost.localdomain> <20181113180008.GA12513@redhat.com> <20181114053837.GA15086@redhat.com> <30cf7af7-8826-55bd-e39a-4f81ed032f6d@suse.de> <20181114174746.GA18526@redhat.com> <87c931e5-4ac9-1795-8d40-cc5541d3ebcf@suse.de> <20181115174605.GA19782@redhat.com> Message-ID: <20181116091458.GA17267@lst.de> On Thu, Nov 15, 2018@12:46:05PM -0500, Mike Snitzer wrote: > Whether or not ANA is present is a choice of the target implementation; > the host (and whether it supports multipathing) has _zero_ influence on > this. If the target declares a path as 'inaccessible' the path _is_ > inaccessible to the host. As such, ANA support should be functional > even if native multipathing is not. > > Introduce ability to always re-read ANA log page as required due to ANA > error and make current ANA state available via sysfs -- even if native > multipathing is disabled on the host (e.g. nvme_core.multipath=N). The first part I could see, but I still want to make it conditional in some way as nvme is going into deeply embedded setups, and I don't want to carry the weight of the ANA code around for everyone. The second I fundamentally disagree with. And even if you found agreement it would have to be in a separate patch as it is a separate feature.