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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A693DC433F5 for ; Tue, 10 May 2022 15:24:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345607AbiEJP2S (ORCPT ); Tue, 10 May 2022 11:28:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345836AbiEJP1P (ORCPT ); Tue, 10 May 2022 11:27:15 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FD665E145; Tue, 10 May 2022 08:16:09 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 88D9E21BB4; Tue, 10 May 2022 15:16:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652195767; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OZqtmv8UjkqRBSiOYZ6ar9KDyJT6hDNxXl9SSULCXTQ=; b=fGhdvJlPt//dq0KQAtVijfj/ESEJ/OC2EKpevE2XN9mzQ9A1L9iCAxeXNQ+pUyb1Mv1UlE HCruB1nKt1ZaJRQk1txzbCvkQt9XnVOQap2jC6oxObMWliWuUvAfiBCulbtCmC4sio8+xa +ZqWsGMsijF1KXpHWJf4ANyjUo2sNOU= Received: from suse.cz (unknown [10.100.208.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 2901B2C141; Tue, 10 May 2022 15:16:06 +0000 (UTC) Date: Tue, 10 May 2022 17:16:01 +0200 From: Petr Mladek To: "Guilherme G. Piccoli" Cc: akpm@linux-foundation.org, bhe@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: Re: [PATCH 14/30] panic: Properly identify the panic event to the notifiers' callbacks Message-ID: References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-15-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220427224924.592546-15-gpiccoli@igalia.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2022-04-27 19:49:08, Guilherme G. Piccoli wrote: > The notifiers infrastructure provides a way to pass an "id" to the > callbacks to determine what kind of event happened, i.e., what is > the reason behind they getting called. > > The panic notifier currently pass 0, but this is soon to be > used in a multi-targeted notifier, so let's pass a meaningful > "id" over there. > > Signed-off-by: Guilherme G. Piccoli > --- > include/linux/panic_notifier.h | 5 +++++ > kernel/panic.c | 2 +- > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h > index 41e32483d7a7..07dced83a783 100644 > --- a/include/linux/panic_notifier.h > +++ b/include/linux/panic_notifier.h > @@ -9,4 +9,9 @@ extern struct atomic_notifier_head panic_notifier_list; > > extern bool crash_kexec_post_notifiers; > > +enum panic_notifier_val { > + PANIC_UNUSED, > + PANIC_NOTIFIER = 0xDEAD, > +}; Hmm, this looks like a hack. PANIC_UNUSED will never be used. All notifiers will be always called with PANIC_NOTIFIER. The @val parameter is normally used when the same notifier_list is used in different situations. But you are going to use it when the same notifier is used in more lists. This is normally distinguished by the @nh (atomic_notifier_head) parameter. IMHO, it is a bad idea. First, it would confuse people because it does not follow the original design of the parameters. Second, the related code must be touched anyway when the notifier is moved into another list so it does not help much. Or do I miss anything, please? Best Regards, Petr