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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 91FBFC10F0E for ; Mon, 15 Apr 2019 10:52:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F73F206B6 for ; Mon, 15 Apr 2019 10:52:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727238AbfDOKwP (ORCPT ); Mon, 15 Apr 2019 06:52:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58360 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727050AbfDOKwO (ORCPT ); Mon, 15 Apr 2019 06:52:14 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 48E3481F18; Mon, 15 Apr 2019 10:52:14 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.38]) by smtp.corp.redhat.com (Postfix) with SMTP id 7BBC319C4F; Mon, 15 Apr 2019 10:52:10 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 15 Apr 2019 12:52:14 +0200 (CEST) Date: Mon, 15 Apr 2019 12:52:09 +0200 From: Oleg Nesterov To: Christian Brauner Cc: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, jannh@google.com, dhowells@redhat.com, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, serge@hallyn.com, luto@kernel.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, tglx@linutronix.de, mtk.manpages@gmail.com, akpm@linux-foundation.org, cyphar@cyphar.com, joel@joelfernandes.org, dancol@google.com Subject: Re: [PATCH 2/4] clone: add CLONE_PIDFD Message-ID: <20190415105209.GA22204@redhat.com> References: <20190414201436.19502-1-christian@brauner.io> <20190414201436.19502-3-christian@brauner.io> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190414201436.19502-3-christian@brauner.io> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 15 Apr 2019 10:52:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/14, Christian Brauner wrote: > > @@ -2260,6 +2363,10 @@ long _do_fork(unsigned long clone_flags, > } > > put_pid(pid); > + > + if (clone_flags & CLONE_PIDFD) > + nr = pidfd; > + Well, this doesn't look nice ... CLONE_PARENT_SETTID doesn't look very usefule, so what if we add if ((clone_flags & (CLONE_PIDFD|CLONE_PARENT_SETTID)) == (CLONE_PIDFD|CLONE_PARENT_SETTID)) return ERR_PTR(-EINVAL); at the start of copy_process() ? Then it can do if (clone_flags & CLONE_PIDFD) { retval = pidfd_create(pid, &pidfdf); if (retval < 0) goto bad_fork_free_pid; retval = put_user(retval, parent_tidptr) if (retval < 0) goto bad_fork_free_pid; } Oleg.