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 9AB63C43217 for ; Tue, 26 Apr 2022 16:01:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352754AbiDZQEP (ORCPT ); Tue, 26 Apr 2022 12:04:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352824AbiDZQEM (ORCPT ); Tue, 26 Apr 2022 12:04:12 -0400 Received: from mail-io1-xd2b.google.com (mail-io1-xd2b.google.com [IPv6:2607:f8b0:4864:20::d2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F677B852 for ; Tue, 26 Apr 2022 09:01:03 -0700 (PDT) Received: by mail-io1-xd2b.google.com with SMTP id 125so20520762iov.10 for ; Tue, 26 Apr 2022 09:01:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dyCNcdxP+OP+ZEEDkKpS4dIut/dFXRkxuAQItAbC2hk=; b=kkI2HO5/ZEBb6dwCosEFba8Hqs93phXW7y7LQIwDiDweskbxzWfkhJOxUXgbksafGv Cj9I3+VUsMtqzbQ+FRheYG7Jnp0nCQoqCtylg9A9uVvjFZFE+gYUol4vZnJS8L/D7fcH IXLA9h7oaFPNuHm4FrQjgkuQGxMTT+zn4y0Dc3ZUaMQ6grfstTlV1uURhTu7yZhAB2CR S15Az/6PGwq5RzEtyE76iZSrukPtIepHVy15uTIKCKRfoQGMqwl6nQ2Wcrtywgqq4l9K yrTT7rEccOM0wyFm2LgURZQ9atXRmAewK37yNCUoS/4n8PFFGhjVqFY7J9psP2v3Z2G9 KjGw== 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=dyCNcdxP+OP+ZEEDkKpS4dIut/dFXRkxuAQItAbC2hk=; b=lj3ZXfzC5jbxSR06Jds3YsToQ+m7QQOEedZ9r4rhkZhgdydjyuVdbce1xSRw5x5Goe 2WYeKmRyXV6WVfrJa1QDmF5/mtVJBpNDogey9Ppa8/nUh/FTWBnjq8zPttxsN2WZgFuu 5MhXH7O+hahPg3EaqBD2ZgTCBKrPV8B0GnLpG00sMmCnUBSBcRziRCORMK1OznZlhaql /X/0h9NLHlImyJJcp4glER/DfLnwXMAS5k5wLUJWBQ7SuriUagjP2eRNJM+s1ma5018P pGn+gjl5Qs67tMGYLz/9fk1SlRMZMArzTcQ/iVSQ8t2TQkF8BxM3ei9EfiZAKBNc/ABY Bmww== X-Gm-Message-State: AOAM532C5vzhI+0D6F0fCC8fXdI1cO/CUJrK+ELwsaF9mWqiM7d7ghLP +gbA9XbbhMJrYSRXO/1AEq3Ha0/wkAz5ok9RVVUNrg== X-Google-Smtp-Source: ABdhPJy2p2YsSAWaLRUyeCx9GIenmVZnYXSr1zBWwbH2S+IZQF4NN6DuvWqwwrbZ5neEqlH8OPqJygq6V4YSc9feqz0= X-Received: by 2002:a05:6638:1695:b0:32a:a178:98bc with SMTP id f21-20020a056638169500b0032aa17898bcmr10205311jat.167.1650988862310; Tue, 26 Apr 2022 09:01:02 -0700 (PDT) MIME-Version: 1.0 References: <20220422212945.2227722-1-axelrasmussen@google.com> <20220422212945.2227722-3-axelrasmussen@google.com> <20220425203249.GA5814@altlinux.org> In-Reply-To: <20220425203249.GA5814@altlinux.org> From: Axel Rasmussen Date: Tue, 26 Apr 2022 09:00:26 -0700 Message-ID: Subject: Re: [PATCH v2 2/6] userfaultfd: add /dev/userfaultfd for fine grained access control To: "Dmitry V. Levin" Cc: Alexander Viro , Andrew Morton , Charan Teja Reddy , Dave Hansen , Gleb Fotengauer-Malinovskiy , Hugh Dickins , Jan Kara , Jonathan Corbet , Mel Gorman , Mike Kravetz , Mike Rapoport , Nadav Amit , Peter Xu , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , zhangyi , linux-api@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, LKML , Linux MM , Linuxkselftest Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org You're right, [1] says _IO is appropriate for ioctls which only take an integer argument. I'll send a v3 with this fix, although I might wait a bit for any other review comments before doing so. Thanks for taking a look! https://www.kernel.org/doc/html/latest/driver-api/ioctl.html On Mon, Apr 25, 2022 at 1:32 PM Dmitry V. Levin wrote: > > On Fri, Apr 22, 2022 at 02:29:41PM -0700, Axel Rasmussen wrote: > [...] > > --- a/include/uapi/linux/userfaultfd.h > > +++ b/include/uapi/linux/userfaultfd.h > > @@ -12,6 +12,10 @@ > > > > #include > > > > +/* ioctls for /dev/userfaultfd */ > > +#define USERFAULTFD_IOC 0xAA > > +#define USERFAULTFD_IOC_NEW _IOWR(USERFAULTFD_IOC, 0x00, int) > > Why this new ioctl is defined using _IOWR()? Since it neither reads from > user memory nor writes into user memory, it should rather be defined using > _IO(), shouldn't it? > > > -- > ldv