From: "Javier González" <javier@javigon.com> To: Christoph Hellwig <hch@lst.de> Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, kbusch@kernel.org, sagi@grimberg.me, minwoo.im.dev@gmail.com Subject: Re: [PATCH V6 1/2] nvme: enable char device per namespace Date: Tue, 9 Mar 2021 13:42:23 +0100 [thread overview] Message-ID: <20210309124104.uowad6bd4vlcthmw@mpHalley.local> (raw) In-Reply-To: <20210309113103.GA9233@lst.de> On 09.03.2021 12:31, Christoph Hellwig wrote: >On Wed, Mar 03, 2021 at 11:02:12AM +0100, Javier González wrote: >>> Ignoring some of the deprecated historic mistakes I think the policy >>> should be: >>> >>> - admin commands that often are controller specific should usually >>> go to a controller-specific device, the existing /dev/nvmeX >>> devices >>> - I/O commands and admin command that do specific a nsid should go >>> through a per-namespace node that is multipath aware and not >>> controller specific >> >> Sounds good. >> >> The current implementation re-routes IOCTLs to the char device through >> the existing bdev IOCTLs, so I believe we follow this policy already. We >> basically default to current behavior. >> >> And I assume that for legacy, namespace IOCTLs to the controller will >> still be routed to the namespace (assuming a single namespace). >> >>> Which also makes me wonder about patch 2 in the series that seems >>> somewhat dangerous. Can we clearly state the policy implemented? >> >> Patch 2 is the one that exposes the existing logic for multipath. How do >> you think we should do it instead? > >So trying to follow the code: > > - nvme_cdev_fops implements file operations that directly on a nvme_ns, > so they are path specific This is correct. > - we allow opening them even for a hidden controller This is also correct. > - there does not seem to be a char device node for ns_head at all. Also correct. We tried to keep it simple in the first iteration. Am I understanding that you see necessary to have per ns_head char devices?
WARNING: multiple messages have this Message-ID (diff)
From: "Javier González" <javier@javigon.com> To: Christoph Hellwig <hch@lst.de> Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, kbusch@kernel.org, sagi@grimberg.me, minwoo.im.dev@gmail.com Subject: Re: [PATCH V6 1/2] nvme: enable char device per namespace Date: Tue, 9 Mar 2021 13:42:23 +0100 [thread overview] Message-ID: <20210309124104.uowad6bd4vlcthmw@mpHalley.local> (raw) In-Reply-To: <20210309113103.GA9233@lst.de> On 09.03.2021 12:31, Christoph Hellwig wrote: >On Wed, Mar 03, 2021 at 11:02:12AM +0100, Javier González wrote: >>> Ignoring some of the deprecated historic mistakes I think the policy >>> should be: >>> >>> - admin commands that often are controller specific should usually >>> go to a controller-specific device, the existing /dev/nvmeX >>> devices >>> - I/O commands and admin command that do specific a nsid should go >>> through a per-namespace node that is multipath aware and not >>> controller specific >> >> Sounds good. >> >> The current implementation re-routes IOCTLs to the char device through >> the existing bdev IOCTLs, so I believe we follow this policy already. We >> basically default to current behavior. >> >> And I assume that for legacy, namespace IOCTLs to the controller will >> still be routed to the namespace (assuming a single namespace). >> >>> Which also makes me wonder about patch 2 in the series that seems >>> somewhat dangerous. Can we clearly state the policy implemented? >> >> Patch 2 is the one that exposes the existing logic for multipath. How do >> you think we should do it instead? > >So trying to follow the code: > > - nvme_cdev_fops implements file operations that directly on a nvme_ns, > so they are path specific This is correct. > - we allow opening them even for a hidden controller This is also correct. > - there does not seem to be a char device node for ns_head at all. Also correct. We tried to keep it simple in the first iteration. Am I understanding that you see necessary to have per ns_head char devices? _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2021-03-09 12:43 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-01 19:24 [PATCH V6 0/2] nvme: enable char device per namespace javier 2021-03-01 19:24 ` javier 2021-03-01 19:24 ` [PATCH V6 1/2] " javier 2021-03-01 19:24 ` javier 2021-03-03 9:10 ` Christoph Hellwig 2021-03-03 9:10 ` Christoph Hellwig 2021-03-03 10:02 ` Javier González 2021-03-03 10:02 ` Javier González 2021-03-09 11:31 ` Christoph Hellwig 2021-03-09 11:31 ` Christoph Hellwig 2021-03-09 12:42 ` Javier González [this message] 2021-03-09 12:42 ` Javier González 2021-03-09 15:05 ` Christoph Hellwig 2021-03-09 15:05 ` Christoph Hellwig 2021-03-09 21:18 ` Javier González 2021-03-09 21:18 ` Javier González 2021-03-24 12:29 ` Niklas Cassel 2021-03-24 12:29 ` Niklas Cassel 2021-03-25 2:09 ` Minwoo Im 2021-03-25 2:09 ` Minwoo Im 2021-03-25 8:26 ` hch 2021-03-25 8:26 ` hch 2021-03-25 8:39 ` Niklas Cassel 2021-03-25 8:39 ` Niklas Cassel 2021-03-25 9:34 ` Minwoo Im 2021-03-25 9:34 ` Minwoo Im 2021-03-25 12:25 ` Niklas Cassel 2021-03-25 12:25 ` Niklas Cassel 2021-03-25 12:33 ` Minwoo Im 2021-03-25 12:33 ` Minwoo Im 2021-03-25 15:14 ` Keith Busch 2021-03-25 15:14 ` Keith Busch 2021-03-01 19:24 ` [PATCH V6 2/2] nvme: allow open for nvme-generic char device javier 2021-03-01 19:24 ` javier
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