From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFE58C433E0 for ; Mon, 15 Feb 2021 17:02:55 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 655EA64DC3 for ; Mon, 15 Feb 2021 17:02:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 655EA64DC3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=8MLEr3UhEOexFRn/3hQGAFjArVXLhh0zkQrTZy1bBwU=; b=TUL1Pou6Dl5skucxTwxlw5Hiu rO3bAfhgvvY9WFNYBZQk9qHu/im3jW2vxopZPeLP+Ox1psZZ/xxhhEuHPYtJHYc9MyxcUGq9+c6qq YYoB9iMAj7HehRehmKqNnliNbcsye6kiuzwSZJpZUdegKec6DJk6ggnff26Hs9I9Rawv5QDdl9UT9 GLdTXBKukN03XDI8XfM3f0favBLdbyN/ICzCMdUmu2yQRtV5flwuZIBvnSboIktrcSgkyGq3VMg+E FvNtqfDo8RpnjjWzu+FlDZh2i82GEd1ksQ9Qg4v1a5uiz8XBjc9gdSk6WrDfXiUJsnADUSn7WU0Vo 4hA9s/NGA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lBhGi-0004Ry-9s; Mon, 15 Feb 2021 17:02:40 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lBhGf-0004RB-Lb for linux-nvme@lists.infradead.org; Mon, 15 Feb 2021 17:02:38 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id A60C361493; Mon, 15 Feb 2021 17:02:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613408556; bh=sVzo63uMXbKBsRipiU46S3L0ZSJ21JAR8qSvhVl6T88=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kQ7Ni/fHotgZ+A76lTA7aIR5UliuaTZlV0KpWJ5ilM9TUZnBzTtDcLCge6PqxgvJB hfhA/FoJqBdbLoEN/mg1KtkMkkcUItrCmI2xCwvObV2zOWCFP7cFqtwgJO7TH6O3vf BfY5XKxSjylddCmFWpRsKCJ3LuGXH3aTWYLhPyy+lg9KfYIJQgUTDkhf2G4B88vi4K 47U/Pf3o6UajG1am+I3wVN9JV0+0DWtis7BbWT/k1tGPcc7MeDXtOBXMLp7U8g43Z+ b+JpMJAlO5xF3wlNTlIo4DSJjE+RPh2AHPmQGNLDp8Rp+wD0swAyu31GeIRlw3OcVY n2KuvMar49dJw== Date: Mon, 15 Feb 2021 09:02:33 -0800 From: Keith Busch To: Minwoo Im Subject: Re: [PATCH] nvme: introduce passthrough ioctl for multipath Message-ID: <20210215170233.GA2707454@dhcp-10-100-145-180.wdc.com> References: <20210214110126.24023-1-minwoo.im.dev@gmail.com> <20210214110126.24023-2-minwoo.im.dev@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210214110126.24023-2-minwoo.im.dev@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210215_120237_799544_2E05EC33 X-CRM114-Status: GOOD ( 13.92 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Christoph Hellwig , linux-nvme@lists.infradead.org, Sagi Grimberg Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Sun, Feb 14, 2021 at 08:01:25PM +0900, Minwoo Im wrote: > We don't allow NVME_IOCTL_IO_CMD ioctl in case that a controller has > multiple namespaces attached. Also, I/O request to the controller > character device has not been recommended and deprecated because we have > block device to I/O with where the multipath consideration is taken. > > Once kernel decided a path to I/O for a namespace based on the I/O > policy of a NVMe subsystem, userspace is not allowed to choose a path to > I/O. If a path is broken(inaccessible state in ANA), then it will not > try to I/O to that path. > > This patch introduced NVME_IOCTL_MPATH_IO command for controller > device(e.g., /dev/nvme0) to support multipath I/O passthrough for > userspace. Regardless driver's path decision, userspace can target a > namespace to I/O. In this case, `cmd.nsid` will be used to find out the > namespace instance target which is hidden(e.g., nvmeXcYnZ). IO commands are not allowed through the character handle with the existing ioctls. A new ioctl doesn't make it okay. If it was okay, then we could just remove the limitation in the current ones. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme