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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 25588CD5BD5 for ; Wed, 27 May 2026 13:27:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RHD5j7gB5Xdgd7LW+ZrE6dndSyx+q5rwokvar81A2+c=; b=jTfp0JmjJ/DAtM/Em3AVmWmhqV V14pOG2Rb4K0iqNbHl3a7WO2T85EfaB05vsL1+79T2jNuPUuPJmsykn77bUouo1A055EbVnSvPP7m rIOwOlNLTp5l7z9XTDnAjs1MY2gVnIb13L3Ygkqw/w0vrHh1tamBalLsZPpBdTGEsftUfIL7B1DwM 5y/LTBrJkB6PtX+j+ZIaB/A5CzVzLwd5ldRYktN9H7gqYzHZPxFD3KZZyXt1uGr4oqrpg+26lN9Hh kNBY9anYBPa7wFft1KLjjIsSch9G96Pv6lWnVFqYrEyLTGY5Bl050JsBpFIIktxE2mW6AzHXLNdIS VhBwI16A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wSEI1-00000004Bqn-3mWX; Wed, 27 May 2026 13:27:17 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wSEI0-00000004BqD-097f for linux-nvme@lists.infradead.org; Wed, 27 May 2026 13:27:16 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id EB12D60229; Wed, 27 May 2026 13:27:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E53E1F000E9; Wed, 27 May 2026 13:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779888434; bh=RHD5j7gB5Xdgd7LW+ZrE6dndSyx+q5rwokvar81A2+c=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=JPahrZwHShfjyDuQ2aMEjQHzzAu9cGToVWE9W2m3NtAu4FaMFlzZCAWaejtw7LxCv LdQt2SYsGWBWZKdF/1x9dX0KXQKqOvul1bMOQvFIdhTTUXQYRcGYKOGedTGg7imAoA P1D3xLzTyWsId7NR3AFdZteKB0SAk1kZAohlOyYwPe9vHqwFxFMnjidPTCAF53MfOn UzC1sNHhWEi5Ey7y7a43pE47KIhxEDxXEnwo7SFLDRCjInNdqSrdQBmLuNEh8qA9w6 bCiOBEHg517GfHqGIAHO6NZzQT5KnKFQO9JOqb5+X3bahIIqNhB1nye7NUxUpjtRGZ bdjx1vmDRNtnA== Date: Wed, 27 May 2026 07:27:12 -0600 From: Keith Busch To: Christoph Hellwig Cc: Keith Busch , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, axboe@kernel.dk, nilay@linux.ibm.com Subject: Re: [PATCHv2 2/2] nvme: add support multipath passthrough iostats Message-ID: References: <20260526153921.2402015-1-kbusch@meta.com> <20260526153921.2402015-3-kbusch@meta.com> <20260527131657.GB10351@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260527131657.GB10351@lst.de> X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, May 27, 2026 at 03:16:57PM +0200, Christoph Hellwig wrote: > On Tue, May 26, 2026 at 08:39:21AM -0700, Keith Busch wrote: > > + struct nvme_ns *ns = q->queuedata; > > struct request *req; > > > > + if (ns && nvme_ns_head_multipath(ns->head)) > > + rq_flags |= REQ_NVME_MPATH; > > I just wanted to come with reasons why it this is wrong, but it actually > seems already - we only have a ns for multipath nodes if multipathing > is enabled. Maybe throw a little comment in on that? Yes. An added subtlety here is that we unconditionally set REQ_FAILFAST_DRIVER for passthrough requests, so it does not get failover consideration. You can't steal bio's from a REQ_DRV_IN/OUT request because all the necessary driver info is attached to the original request, which doesn't follow the bio.