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=-12.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 DDBA7C433F5 for ; Wed, 8 Sep 2021 19:15:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3B0561163 for ; Wed, 8 Sep 2021 19:15:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349551AbhIHTQi (ORCPT ); Wed, 8 Sep 2021 15:16:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241184AbhIHTQh (ORCPT ); Wed, 8 Sep 2021 15:16:37 -0400 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5E36C061757 for ; Wed, 8 Sep 2021 12:15:29 -0700 (PDT) Received: by mail-io1-xd2a.google.com with SMTP id q3so4697189iot.3 for ; Wed, 08 Sep 2021 12:15:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=mjDGouD+M9yKQtkIm/4GL2bnggnKQCdFLvusLC3KaDY=; b=SmfnVW9cLbCsKjgfyTfU0MHE84dmfcvVpd53zYbVhMwKx/We0L46qHRL4qfFxfLoC4 aOXVuRHhTrZkhDuP4tqQthID4FqOScs0GLbufoTpIgzws7SCMPixYeVPkTUQeGPtN4iU 8SJdOnZr3ybMR4ygUc6/7gOe0tc88iDy+oLGKT3t3O4TBORyCsTOgf8vEVqGm83zKxHa 3vR2iWZj8cEtO7vQhviL726O15JHnAonuylEUgcgKaQQQJ5kTo04CmW8xZI6l4G7euu6 nyzpp1FC2stcKsDDPvNQYzGlDsOPZjD3Vqw5hY2hJxaLH02O3kT/FLtK2GQN6elPr6hk jzzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=mjDGouD+M9yKQtkIm/4GL2bnggnKQCdFLvusLC3KaDY=; b=rWrfkgfToRptDRcDe0YH1PEzKFrv4OJEIGtMglxZsAeLOLa+lSZzp/nO6IyiZwTLdB e81NoLqYwN4FF5+W/kmCm29aYVGXM8HJQyJ88gU7Du5sA34k90WeDSdDiWjZzv+f52Wc Mbhzu1PSpIeIcJyagmBv8lJ8PDvnMGc5lXHRBl0pepC7ChxBghyp53hefGfact51966q de/q9DgHU08qifuNkrOHYbLjmeWx234dxza9gGRQg2cqDujcHQ9io3As94kSnxthQ6p5 YvzlZa7Rn065XFN3uwddXfwHhuTkC9Bbzz7xhf7oluVxkFVTGDVzQ6fTun3z/4gMZS7j tqrQ== X-Gm-Message-State: AOAM5301uiC+hcJ0kXRXPg5rrfgwqGC5Y3TAvULQ3nos+HPQgG5JC+uw k+nhMjayTX4NKO8XSS+RXu7PODyTQTUmqA== X-Google-Smtp-Source: ABdhPJxWJ2sGn5YEaol+LSukYkii0hC5K7GfDJ5DpWi+Dn0qUf5qdFNJJxvzAcpplNMW43xRV4UC9w== X-Received: by 2002:a02:2402:: with SMTP id f2mr5220765jaa.28.1631128529061; Wed, 08 Sep 2021 12:15:29 -0700 (PDT) Received: from [192.168.1.116] ([66.219.217.159]) by smtp.gmail.com with ESMTPSA id j14sm678625ile.39.2021.09.08.12.15.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Sep 2021 12:15:28 -0700 (PDT) Subject: Re: [PATCH v2] /dev/mem: nowait zero/null ops To: Pavel Begunkov , Arnd Bergmann , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Cc: io-uring@vger.kernel.org References: From: Jens Axboe Message-ID: <9370d400-3944-b62a-65f6-5c31ac86ea35@kernel.dk> Date: Wed, 8 Sep 2021 13:15:27 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 9/8/21 1:10 PM, Pavel Begunkov wrote: > Make read_iter_zero() to honor IOCB_NOWAIT, so /dev/zero can be > advertised as FMODE_NOWAIT. It's useful for io_uring, which needs it to > apply certain optimisations when doing I/O against the device. > > Set FMODE_NOWAIT for /dev/null as well, it never waits and therefore > trivially meets the criteria. Reviewed-by: Jens Axboe -- Jens Axboe