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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 8795DC54FC9 for ; Tue, 21 Apr 2020 15:08:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DF30206D6 for ; Tue, 21 Apr 2020 15:08:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728841AbgDUPIS (ORCPT ); Tue, 21 Apr 2020 11:08:18 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:39462 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726628AbgDUPIS (ORCPT ); Tue, 21 Apr 2020 11:08:18 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jQuVU-0005rQ-Qg; Tue, 21 Apr 2020 09:08:16 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jQuVU-000873-0g; Tue, 21 Apr 2020 09:08:16 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Oleg Nesterov Cc: linux-kernel@vger.kernel.org, Christof Meerwald , Linux Containers References: <20200419201336.GI22017@edge.cmeerw.net> <87sggyytnh.fsf@x220.int.ebiederm.org> <20200421090426.GA6787@redhat.com> <20200421101904.GA9358@redhat.com> Date: Tue, 21 Apr 2020 10:05:10 -0500 In-Reply-To: <20200421101904.GA9358@redhat.com> (Oleg Nesterov's message of "Tue, 21 Apr 2020 12:19:04 +0200") Message-ID: <87mu74517d.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jQuVU-000873-0g;;;mid=<87mu74517d.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19Yjwrl5mq9JkJujsk7jmlVVXuCbMojEnw= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH] remove the no longer needed pid_alive() check in __task_pid_nr_ns() X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Oleg Nesterov writes: > Starting from 2c4704756cab ("pids: Move the pgrp and session pid pointers > from task_struct to signal_struct") __task_pid_nr_ns() doesn't dereference > task->group_leader, we can remove the pid_alive() check. > > pid_nr_ns() has to check pid != NULL anyway, pid_alive() just adds the > unnecessary confusion. > > Signed-off-by: Oleg Nesterov Reviewed-by: "Eric W. Biederman" > --- Good catch that does simplify things. Eric > kernel/pid.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/pid.c b/kernel/pid.c > index bc21c0fb26d8..47221db038e2 100644 > --- a/kernel/pid.c > +++ b/kernel/pid.c > @@ -475,8 +475,7 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, > rcu_read_lock(); > if (!ns) > ns = task_active_pid_ns(current); > - if (likely(pid_alive(task))) > - nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns); > + nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns); > rcu_read_unlock(); > > return nr;