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Tue, 01 Dec 2020 19:00:45 -0800 (PST) Date: Wed, 2 Dec 2020 12:00:43 +0900 From: Minwoo Im To: Keith Busch Cc: Javier =?utf-8?B?R29uesOhbGV6?= , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, hch@lst.de, sagi@grimberg.me Subject: Re: [PATCH 4/4] nvme: enable char device per namespace Message-ID: <20201202030043.GA21178@localhost.localdomain> References: <20201201125610.17138-1-javier.gonz@samsung.com> <20201201125610.17138-5-javier.gonz@samsung.com> <20201201140348.GA5138@localhost.localdomain> <20201201185732.unlurqed2kaqwjsb@MacBook-Pro.localdomain> <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com> User-Agent: Mutt/1.11.4 (2019-03-13) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 20-12-02 04:30:02, Keith Busch wrote: > On Tue, Dec 01, 2020 at 07:57:32PM +0100, Javier González wrote: > > On 01.12.2020 23:03, Minwoo Im wrote: > > > > + > > > > + device_initialize(&ns->cdev_device); > > > > + ns->cdev_device.devt = MKDEV(MAJOR(nvme_ns_base_chr_devt), > > > > + ns->head->instance); > > > > + ns->cdev_device.class = nvme_ns_class; > > > > + ns->cdev_device.parent = ctrl->device; > > > > + ns->cdev_device.groups = nvme_ns_char_id_attr_groups; > > > > + dev_set_drvdata(&ns->cdev_device, ns); > > > > + > > > > + sprintf(cdisk_name, "nvme%dc%dn%d", ctrl->subsys->instance, > > > > + ctrl->instance, ns->head->instance); > > > > > > In multi-path, private namespaces for a head are not in /dev, so I don't > > > think this will hurt private namespaces (e.g., nvme0c0n1), But it looks > > > like it will make a little bit confusions between chardev and hidden blkdev. > > > > > > I don't against to update nvme-cli things also even naming conventions are > > > going to become different than nvmeXcYnZ. > > > > Agree. But as I understand it, Keith had a good argument to keep names > > aligned with the hidden bdev. > > My suggested naming makes it as obvious as possible that the character > device in /dev/ and the hidden block device in /sys/ are referring to > the same thing. What is confusing about that? I meant that someone might misunderstand tht /dev/nvmeXcYnZ is also a blkdev just like /dev/nvmeXnY. I'm just saying it might be, but I'm fine with suggested naming as those two are indicating a single concept (namespace).