From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751858AbWFTXXp (ORCPT ); Tue, 20 Jun 2006 19:23:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751860AbWFTXXp (ORCPT ); Tue, 20 Jun 2006 19:23:45 -0400 Received: from omta02sl.mx.bigpond.com ([144.140.93.154]:45750 "EHLO omta02sl.mx.bigpond.com") by vger.kernel.org with ESMTP id S1751858AbWFTXXo (ORCPT ); Tue, 20 Jun 2006 19:23:44 -0400 Message-ID: <4498837E.7040203@bigpond.net.au> Date: Wed, 21 Jun 2006 09:23:42 +1000 From: Peter Williams User-Agent: Thunderbird 1.5.0.2 (X11/20060501) MIME-Version: 1.0 To: Andrew Morton CC: Matt Helsley , nagar@watson.ibm.com, sekharan@us.ibm.com, jtk@us.ibm.com, balbir@in.ibm.com, jes@sgi.com, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, lse-tech@lists.sourceforge.net Subject: Re: [Lse-tech] [PATCH 09/11] Task watchers: Add support for per-task watchers References: <20060613235122.130021000@localhost.localdomain> <1150242901.21787.149.camel@stark> <44978793.8070109@bigpond.net.au> <1150844177.21787.774.camel@stark> <20060620161524.7c132eea.akpm@osdl.org> In-Reply-To: <20060620161524.7c132eea.akpm@osdl.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Authentication-Info: Submitted using SMTP AUTH PLAIN at omta02sl.mx.bigpond.com from [147.10.133.38] using ID pwil3058@bigpond.net.au at Tue, 20 Jun 2006 23:23:42 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > Matt Helsley wrote: >>>> +static inline int notify_per_task_watchers(unsigned int val, >>>> + struct task_struct *task) >>>> +{ >>>> + if (get_watch_event(val) != WATCH_TASK_INIT) >>>> + return raw_notifier_call_chain(&task->notify, val, task); >>>> + RAW_INIT_NOTIFIER_HEAD(&task->notify); >>>> + if (task->real_parent) >>>> + return raw_notifier_call_chain(&task->real_parent->notify, >>>> + val, task); >>>> +} >>> It's possible for this task to exit without returning a result. >> Assuming you meant s/task/function/: >> >> In the common case this will return a result because most tasks have a >> real parent. The only exception should be the init task. However, the >> init task does not "fork" from another task so this function will never >> get called with WATCH_TASK_INIT and the init task. >> >> This means that if one wants to use per-task watchers to associate data >> and a function call with *every* task, special care will need to be >> taken to register with the init task. > > no...... > > It's possible for this function to fall off the end without returning > anything. The compiler should have spat a warning. I checked and it does. -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce