From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753587Ab2CKRi0 (ORCPT ); Sun, 11 Mar 2012 13:38:26 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:59229 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753474Ab2CKRiY (ORCPT ); Sun, 11 Mar 2012 13:38:24 -0400 Message-ID: <1331487502.2449.20.camel@edumazet-laptop> Subject: Re: [V2 PATCH 1/3] module: use rcu to protect module list read From: Eric Dumazet To: Cong Wang Cc: linux-kernel@vger.kernel.org, Andrew Morton , "Paul E. McKenney" , Rusty Russell Date: Sun, 11 Mar 2012 10:38:22 -0700 In-Reply-To: <1331463255-31019-1-git-send-email-xiyou.wangcong@gmail.com> References: <1331463255-31019-1-git-send-email-xiyou.wangcong@gmail.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2- Content-Transfer-Encoding: 8bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le dimanche 11 mars 2012 à 18:54 +0800, Cong Wang a écrit : > V2: ... > > @@ -1639,7 +1639,7 @@ static void mod_sysfs_teardown(struct module *mod) > static int __unlink_module(void *_mod) > { > struct module *mod = _mod; > - list_del(&mod->list); > + list_del_rcu(&mod->list); > module_bug_cleanup(mod); > return 0; > } > @@ You mix too many different things in a single patch. For example, lets review this __unlink_module() change... If this was really needed, it should be a single patch so that it can be a stable submission. As it is not needed (since its called from stop_machine()), this makes your whole patch looking suspicious. I suggest you make a 100% cleanup patch, changing the title as well, because module code _already_ uses RCU. "module: use rcu to protect module list read" makes no sense at all. To meet current RCU API best pratices, you change preempt_enable() by rcu_read_unlock_sched() and preempt_disable() by rcu_read_lock_sched() Then, if you believe other changes are needed, submit them with an explicit changelog explaining the change, not hiding them in a big cleanup patch. Ref: Documentation/SubmittingPatches section 3)