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 281D3C433F5 for ; Mon, 25 Apr 2022 20:32:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8B70C6B00B0; Mon, 25 Apr 2022 16:32:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 865336B00B1; Mon, 25 Apr 2022 16:32:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 72D5D6B00B2; Mon, 25 Apr 2022 16:32:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 5FF2F6B00B0 for ; Mon, 25 Apr 2022 16:32:52 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 344576268C for ; Mon, 25 Apr 2022 20:32:52 +0000 (UTC) X-FDA: 79396550184.11.AE52865 Received: from vmicros1.altlinux.org (vmicros1.altlinux.org [194.107.17.57]) by imf16.hostedemail.com (Postfix) with ESMTP id 80BD8180057 for ; Mon, 25 Apr 2022 20:32:48 +0000 (UTC) Received: from mua.local.altlinux.org (mua.local.altlinux.org [192.168.1.14]) by vmicros1.altlinux.org (Postfix) with ESMTP id 05C0172C8DC; Mon, 25 Apr 2022 23:32:50 +0300 (MSK) Received: by mua.local.altlinux.org (Postfix, from userid 508) id E672E7CE7A3; Mon, 25 Apr 2022 23:32:49 +0300 (MSK) Date: Mon, 25 Apr 2022 23:32:49 +0300 From: "Dmitry V. Levin" To: Axel Rasmussen 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, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v2 2/6] userfaultfd: add /dev/userfaultfd for fine grained access control Message-ID: <20220425203249.GA5814@altlinux.org> References: <20220422212945.2227722-1-axelrasmussen@google.com> <20220422212945.2227722-3-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220422212945.2227722-3-axelrasmussen@google.com> X-Rspamd-Queue-Id: 80BD8180057 X-Stat-Signature: s7ud8ohq7uko47ayjq7hpcqjyb1eaay8 Authentication-Results: imf16.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf16.hostedemail.com: domain of ldv@altlinux.org designates 194.107.17.57 as permitted sender) smtp.mailfrom=ldv@altlinux.org X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1650918768-853989 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 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