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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6335BC433EF for ; Mon, 28 Feb 2022 15:59:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E2428D0002; Mon, 28 Feb 2022 10:59:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 891BE8D0001; Mon, 28 Feb 2022 10:59:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7808D8D0002; Mon, 28 Feb 2022 10:59:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id 6CFFB8D0001 for ; Mon, 28 Feb 2022 10:59:47 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 3A698213BA for ; Mon, 28 Feb 2022 15:59:47 +0000 (UTC) X-FDA: 79192649214.02.7A0EB04 Received: from mail-ej1-f54.google.com (mail-ej1-f54.google.com [209.85.218.54]) by imf14.hostedemail.com (Postfix) with ESMTP id 52E9910000E for ; Mon, 28 Feb 2022 15:59:46 +0000 (UTC) Received: by mail-ej1-f54.google.com with SMTP id a23so25714387eju.3 for ; Mon, 28 Feb 2022 07:59:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=udUUwQMYZOQdeQeu7KJflNOXp5UljA8CQOPQlhHKm+Y=; b=Ps2g3Rmx7y+RxaExNigUlAShr8r9n4HJx4jXh3jX3l48QN2GGz17bPjHQGFh/RPT/a Xe3Y302EzQSNvW7VzbwzWaqmO5xMMVqpxy+XXofnecS/u0ED0x+tbYTlqkSLsLRhSciu N6rSkzsDR47sLeOm/7rAJXCL4mb6S7A5gjjMA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=udUUwQMYZOQdeQeu7KJflNOXp5UljA8CQOPQlhHKm+Y=; b=L2vivCnLxCeGpdy/RaZ0eZa9mehNj41RFMxeIOlVfCbA463OrBz+rsfSGyvWZmUX7y UvexDenTIqCGTa6e3nig2EEQYWtPwDv5fJ8zwVv2S6RRS3Uw2RwWOXHTIgVhlzfAsxe5 LvU4YY7RrnU9+PrtoYYLQvfvcZW2u2u9n35+nP5dHezsarddQ0pxnCAaeiFFaEpAlvle tynMcztKu3kOh76IN1FB2CHXgCWzI0d4yZZffzqqijJjTBSN005vMW1fnMQ+16xXURhy oFOVuF8nO+7BM6xEaBXG7hzJ3IlbTTu4O7VbzSv5ZoZzfSkwycaRSxgmyOqbZe6qS4Qd drQA== X-Gm-Message-State: AOAM531QnQbD6B0Q+vrA/Ta7rA7X8PqVPRX3n8LmQjlDUDyh29zRGlu1 ourKamkwyPbhkU10KfknyetsdWtHaZzaBkXh/fZLfg== X-Google-Smtp-Source: ABdhPJzFuwC4cXK43NRFP1CzDPmxJHkeyiho2pckN/boPKiQ0vuUKSn6l1ZxMqIRvXXEFW5bhRCbL2ZNT2f45sLUzvo= X-Received: by 2002:a17:907:76fc:b0:6ce:a836:34a1 with SMTP id kg28-20020a17090776fc00b006cea83634a1mr16312616ejc.663.1646063984879; Mon, 28 Feb 2022 07:59:44 -0800 (PST) MIME-Version: 1.0 References: <20220227093434.2889464-1-jhubbard@nvidia.com> <20220227093434.2889464-7-jhubbard@nvidia.com> In-Reply-To: <20220227093434.2889464-7-jhubbard@nvidia.com> From: Miklos Szeredi Date: Mon, 28 Feb 2022 16:59:33 +0100 Message-ID: Subject: Re: [PATCH 6/6] fuse: convert direct IO paths to use FOLL_PIN To: jhubbard.send.patches@gmail.com Cc: Jens Axboe , Jan Kara , Christoph Hellwig , Dave Chinner , "Darrick J . Wong" , "Theodore Ts'o" , Alexander Viro , Andrew Morton , Chaitanya Kulkarni , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs , linux-mm , LKML , John Hubbard Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 52E9910000E X-Rspam-User: Authentication-Results: imf14.hostedemail.com; dkim=none ("invalid DKIM record") header.d=szeredi.hu header.s=google header.b=Ps2g3Rmx; spf=pass (imf14.hostedemail.com: domain of miklos@szeredi.hu designates 209.85.218.54 as permitted sender) smtp.mailfrom=miklos@szeredi.hu; dmarc=none X-Stat-Signature: g6uw5hy7d8gphww7g9mu7isqqugywsb1 X-HE-Tag: 1646063986-105370 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 27 Feb 2022 at 10:34, wrote: > > From: John Hubbard > > Convert the fuse filesystem to support the new iov_iter_get_pages() > behavior. That routine now invokes pin_user_pages_fast(), which means > that such pages must be released via unpin_user_page(), rather than via > put_page(). > > This commit also removes any possibility of kernel pages being handled, > in the fuse_get_user_pages() call. Although this may seem like a steep > price to pay, Christoph Hellwig actually recommended it a few years ago > for nearly the same situation [1]. This might work for O_DIRECT, but fuse has this mode of operation which turns normal "buffered" I/O into direct I/O. And that in turn will break execve of such files. So AFAICS we need to keep kvec handing in some way. Thanks, Miklos