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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 9FD86C433DB for ; Mon, 15 Feb 2021 16:10:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 658D664DEE for ; Mon, 15 Feb 2021 16:10:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232046AbhBOQJQ (ORCPT ); Mon, 15 Feb 2021 11:09:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232916AbhBOQGc (ORCPT ); Mon, 15 Feb 2021 11:06:32 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D427AC0613D6; Mon, 15 Feb 2021 08:04:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ABknkne7Nrn83Z017RdB6TUScjJdC65GnVh/Mnzaro4=; b=OhNLW94ejUS39Nx7GhTuQ7ezdo q5Wb7HXw3WDjDr/XnEMyiKNF5Uxs9VTjZBW+3vEUNADCSPX5PvM77kgXHpbL7bgAujmpCQ5cflRMe tTgMXTJRBXrL7pptc1mjtI4Jb+Qby+L9ULklOfDMW0Dl/q7eIbus7Trt8VNc+I11PIct7CPbs7t8D 0PeT8FwhMlogzUvkCLX9hiAhpOezlGe1hVcHmhsWIwL93pymNLCGpOaHgh+7EqwwQL8oYfRkyi1uW igN+zxx/JApi6jslEPnSmi77+yruJVv/f3P68A4EU9er5WeSclCa3/+wZCUuIxe0eSgGCmWJOYPTg L2U9YsRQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lBgM7-00Fky1-Ex; Mon, 15 Feb 2021 16:04:20 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 430053007CD; Mon, 15 Feb 2021 17:04:10 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2CD1D20431BC4; Mon, 15 Feb 2021 17:04:10 +0100 (CET) Date: Mon, 15 Feb 2021 17:04:10 +0100 From: Peter Zijlstra To: Johannes Berg Cc: Shuah Khan , mingo@redhat.com, will@kernel.org, kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org, ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] lockdep: add lockdep_assert_not_held() Message-ID: References: <37a29c383bff2fb1605241ee6c7c9be3784fb3c6.1613171185.git.skhan@linuxfoundation.org> <20210215104402.GC4507@worktop.programming.kicks-ass.net> <79aeb83a288051bd3a2a3f15e5ac42e06f154d48.camel@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <79aeb83a288051bd3a2a3f15e5ac42e06f154d48.camel@sipsolutions.net> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Feb 15, 2021 at 02:12:30PM +0100, Johannes Berg wrote: > On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote: > > > > I think something like so will work, but please double check. > > Yeah, that looks better. > > > +++ b/include/linux/lockdep.h > > @@ -294,11 +294,15 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); > > > > #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) > > > > -#define lockdep_assert_held(l) do { \ > > - WARN_ON(debug_locks && !lockdep_is_held(l)); \ > > +#define lockdep_assert_held(l) do { \ > > + WARN_ON(debug_locks && lockdep_is_held(l) == 0)); \ > > } while (0) > > That doesn't really need to change? It's the same. Correct, but I found it more symmetric vs the not implementation below. > > -#define lockdep_assert_held_write(l) do { \ > > +#define lockdep_assert_not_held(l) do { \ > > + WARN_ON(debug_locks && lockdep_is_held(l) == 1)); \ > > + } while (0) > > + > > +#define lockdep_assert_held_write(l) do { \ > > WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \ > > } while (0) > > > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > > index c1418b47f625..983ba206f7b2 100644 > > --- a/kernel/locking/lockdep. > > +++ b/kernel/locking/lockdep.c > > @@ -5467,7 +5467,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read) > > int ret = 0; > > > > if (unlikely(!lockdep_enabled())) > > - return 1; /* avoid false negative lockdep_assert_held() */ > > + return -1; /* avoid false negative lockdep_assert_held() */ > > Maybe add lockdep_assert_not_held() to the comment, to explain the -1 > (vs non-zero)? Yeah, or frob a '*' in there.