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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACF8BC433EF for ; Wed, 16 Mar 2022 13:52:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354524AbiCPNyI (ORCPT ); Wed, 16 Mar 2022 09:54:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354231AbiCPNyG (ORCPT ); Wed, 16 Mar 2022 09:54:06 -0400 Received: from mail-wr1-f47.google.com (mail-wr1-f47.google.com [209.85.221.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D63231A0; Wed, 16 Mar 2022 06:52:49 -0700 (PDT) Received: by mail-wr1-f47.google.com with SMTP id r10so3100398wrp.3; Wed, 16 Mar 2022 06:52:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=g2JpBcc/NKpDAPZChPw+W7kZSZTO1SHhUlKPE+wqy+c=; b=cEXPzBe9iZJm8x8F+SKEPIItgducZEaCyqnlFWGGi4JXCBL+DbK0v8TIVJkyQTbSHr HeF+X1kqQ/buOojXUcMStApxgE+F8jeX3GOPgPLr3ginXS6UHTEd5sgIg+GAgDKRWQHc zcj8lZlWp1lUWjvfY3+/fbvtk/NZfnRIgBvopFhtVj/RXtCLwZJQyMnVhY92gRoj6BTL PANi75cNCM5Gypf2WoPzORTIs0YltItrKJRH3VBsQ5Bm7zLZe92ZBd8kS/hC5gI67srq lim8ZPZjTtOio7guPNKnWVf31y1szBgrTbDuck9pD9lJQCMtXGe/Xm4jL2Dk96JVVuet GrKg== X-Gm-Message-State: AOAM533uIp5/ecF+RqP4hQ22fUyD2R4q28yuzsQCGKdDN3ZP2xKzvcMf eM+oPFkawDUA1RL35iZSJv8= X-Google-Smtp-Source: ABdhPJwLwWzFdFkbUnONXVDVXs/3GZdMiKVABbSaSYh1u911dOx3621EujfQC+sGuf1CeLp19Qm79A== X-Received: by 2002:a5d:55c5:0:b0:1f0:7672:637d with SMTP id i5-20020a5d55c5000000b001f07672637dmr101416wrw.170.1647438768337; Wed, 16 Mar 2022 06:52:48 -0700 (PDT) Received: from [192.168.64.180] (bzq-219-42-90.isdn.bezeqint.net. [62.219.42.90]) by smtp.gmail.com with ESMTPSA id e10-20020a056000178a00b0020393321552sm1921536wrg.85.2022.03.16.06.52.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 16 Mar 2022 06:52:47 -0700 (PDT) Message-ID: <3ed01280-5487-7206-a326-0cd110118b65@grimberg.me> Date: Wed, 16 Mar 2022 15:52:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 05/17] nvme: wire-up support for async-passthru on char-device. Content-Language: en-US To: Kanchan Joshi Cc: Kanchan Joshi , Jens Axboe , Christoph Hellwig , Keith Busch , Pavel Begunkov , io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, sbates@raithlin.com, logang@deltatee.com, Pankaj Raghav , =?UTF-8?Q?Javier_Gonz=c3=a1lez?= , Luis Chamberlain , Adam Manzanares , Anuj Gupta References: <20220308152105.309618-1-joshi.k@samsung.com> <20220308152105.309618-6-joshi.k@samsung.com> <7a123895-1102-4b36-2d6e-1e00e978d03d@grimberg.me> <8f45a761-5ecb-5911-1064-9625a285c93d@grimberg.me> <20220316092153.GA4885@test-zns> <11f9e933-cfc8-2e3b-c815-c49a4b7db4ec@grimberg.me> From: Sagi Grimberg In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org >>>>>> No one cares that this has no multipathing capabilities what-so-ever? >>>>>> despite being issued on the mpath device node? >>>>>> >>>>>> I know we are not doing multipathing for userspace today, but this >>>>>> feels like an alternative I/O interface for nvme, seems a bit cripled >>>>>> with zero multipathing capabilities... [...] > Got it, thanks. Passthrough (sync or async) just returns the failure > to user-space if that fails. > No attempt to retry/requeue as the block path does. I know, and that was my original question, no one cares that this interface completely lacks this capability? Maybe it is fine, but it is not a trivial assumption given that this is designed to be more than an interface to send admin/vs commands to the controller...