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 855B1C71153 for ; Mon, 11 Sep 2023 02:12:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232531AbjIKCMX (ORCPT ); Sun, 10 Sep 2023 22:12:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231703AbjIKCMW (ORCPT ); Sun, 10 Sep 2023 22:12:22 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD896189 for ; Sun, 10 Sep 2023 19:11:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694398286; h=from:from:reply-to:subject:subject: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=Mjb3hdzORQdy0trp+gr35cXqM14i405hB8hckdOimd4=; b=IA/d8zg1P3H2tyogdZr5NMrXJDhYRzazHQtxaK4Mzm6HjpE46MoKZ8n0BBBsDi6RiZYApL GAuHvluD/LxAhpgypVVYLomGCBE9hugXWefnP0yLxhWjgyYGEwskLKhm2nk7XJkFCxKWrt diSQ8D7RTP1lgPPqXq+V195mIJkdEVQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-562-ysgnE0wQPCqLPd2fK3TVMw-1; Sun, 10 Sep 2023 22:11:21 -0400 X-MC-Unique: ysgnE0wQPCqLPd2fK3TVMw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EF9DD29AB3FF; Mon, 11 Sep 2023 02:11:20 +0000 (UTC) Received: from localhost (unknown [10.72.112.35]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AAE5C2015CFF; Mon, 11 Sep 2023 02:11:19 +0000 (UTC) Date: Mon, 11 Sep 2023 10:11:16 +0800 From: Baoquan He To: "Leizhen (ThunderTown)" Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, catalin.marinas@arm.com, thunder.leizhen@huawei.com, dyoung@redhat.com, prudo@redhat.com, samuel.holland@sifive.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org Subject: Re: [PATCH v2 3/8] crash_core: change parse_crashkernel() to support crashkernel=,high|low parsing Message-ID: References: <20230829121610.138107-1-bhe@redhat.com> <20230829121610.138107-4-bhe@redhat.com> <2b9af1b7-8d80-46b7-d582-156a97456a36@huaweicloud.com> <58a0c4be-0302-04e0-8723-df37407884a8@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <58a0c4be-0302-04e0-8723-df37407884a8@huaweicloud.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/06/23 at 05:07pm, Leizhen (ThunderTown) wrote: > > > On 2023/9/5 16:29, Baoquan He wrote: > > On 09/04/23 at 10:47am, Leizhen (ThunderTown) wrote: > >> > >> > >> On 2023/9/1 17:49, Baoquan He wrote: > >>>>> + > >>>>> + *high = true; > >>>>> + } else if (ret || !*crash_size) { > >>>> This check can be moved outside of #ifdef. Because even '!high', it's completely > >>>> applicable. The overall adjustment is as follows: > >>> Hmm, the current logic is much easier to understand. However, I may not > >>> 100% get your suggestion. Can you paste the complete code in your > >>> suggested way? Do not need 100% correct code, just the skeleton of code logic > >>> so that I can better understand it and add inline comment. > >> > >> int __init parse_crashkernel(...) > >> { > >> int ret; > >> > >> /* crashkernel=X[@offset] */ > >> ret = __parse_crashkernel(cmdline, system_ram, crash_size, > >> crash_base, NULL); > >> > >> #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION > >> if (high && ret == -ENOENT) { > >> ... ... //The code for your original branch "else if (ret == -ENOENT) {" > >> ret = 0; //Added based on the next discussion > >> } > >> +#endif > >> > >> if (!*crash_size) > >> ret = -EINVAL; > >> > >> return ret; > >> } > >> > > Thanks, Zhen Lei. > > > > I paste the whole parse_crashkernel() as you suggested at bottom. Please > > check if it's what you want. > > Yes. > > > To me, both is fine to me. I have two minor > > concerns to your suggested way. > > > > 1) > > I took the "if (!high) return" way because except of x86/arm64, all > > other architectures will call parse_crashkerne() and check > > if *crash_size ==0. Please try 'git grep "parse_crashkernel(" arch' > > and check those call sites. With that, we will have duplicated checking. > > Add some patches to remove the duplicated checking of other ARCHs? After this > patch series upstreamed. I resisted this in the first place, after rethinking, it makes sense. parse_crashkernel() returning 0 indicates a meaningful crashkernel vlaue parsed, otherwise non-zero. I will go with this. > > > > > ret = __parse_crashkernel(cmdline, system_ram, crash_size, > > crash_base, NULL); > > if (!high) > > return ret; > > 2) > > I actually like below branch and the code comment. It can give people > > hint about what's going on in that case. Discarding it is a little pity. > > Except that "!*crash_size" and "(high && ret == -ENOENT)" needs special comments, > other common errors do not need to be described, I think. Even if some is required, > it should be placed in function __parse_crashkernel(). Hmm, I will consider how to comment these better, will update and post v3. Thanks, Lei. > > > > > } else if (ret || !*crash_size) { > > /* The specified value is invalid */ > > return -1; > > } > > > > int __init parse_crashkernel(...) > > { > > int ret; > > > > /* crashkernel=X[@offset] */ > > ret = __parse_crashkernel(cmdline, system_ram, crash_size, > > crash_base, NULL); > > #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION > > if (high && ret == -ENOENT) { > > ret = __parse_crashkernel(cmdline, 0, crash_size, > > crash_base, suffix_tbl[SUFFIX_HIGH]); > > if (ret || !*crash_size) > > return -EINVAL; > > > > /* > > * crashkernel=Y,low can be specified or not, but invalid value > > * is not allowed. > > */ > > ret = __parse_crashkernel(cmdline, 0, low_size, > > crash_base, suffix_tbl[SUFFIX_LOW]); > > if (ret == -ENOENT) { > > *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; > > ret = 0; > > } else if (ret) { > > return ret; > > } > > > > *high = true; > > } > > #endif > > > > if (!*crash_size) > > ret = -EINVAL; > > > > return ret; > > } > > > > . > > > > -- > Regards, > Zhen Lei >