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Date:   Thu, 31 May 2018 18:34:40 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Mike Snitzer <snitzer@redhat.com>
Cc:     Sagi Grimberg <sagi@grimberg.me>, Christoph Hellwig <hch@lst.de>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Keith Busch <keith.busch@intel.com>,
        Hannes Reinecke <hare@suse.de>,
        Laurence Oberman <loberman@redhat.com>,
        Ewan Milne <emilne@redhat.com>,
        James Smart <james.smart@broadcom.com>,
        Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
        Linux NVMe Mailinglist <linux-nvme@lists.infradead.org>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        Martin George <marting@netapp.com>,
        John Meneghini <John.Meneghini@netapp.com>
Subject: Re: [PATCH 0/3] Provide more fine grained control over multipathing
Message-ID: <20180531163440.GB30954@lst.de>
References: <20180525125322.15398-1-jthumshirn@suse.de> <20180525130535.GA24239@lst.de> <20180525135813.GB9591@redhat.com> <db1aa53f-1152-c003-ccc1-3e439ca6916d@grimberg.me> <20180530220206.GA7037@redhat.com> <f084e3bc-77af-4268-c882-7b0737e45f3b@grimberg.me> <20180531123738.GA10552@redhat.com>
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On Thu, May 31, 2018 at 08:37:39AM -0400, Mike Snitzer wrote:
> I saw your reply to the 1/3 patch.. I do agree it is broken for not
> checking if any handles are active.  But that is easily fixed no?

Doing a switch at runtime simply is a really bad idea.  If for some
reason we end up with a good per-controller switch it would have
to be something set at probe time, and to get it on a controller
you'd need to reset it first.