From patchwork Thu Jan 23 01:41:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cao jin X-Patchwork-Id: 11346677 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 45A946C1 for ; Thu, 23 Jan 2020 01:42:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D99E24673 for ; Thu, 23 Jan 2020 01:42:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728809AbgAWBly (ORCPT ); Wed, 22 Jan 2020 20:41:54 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:44226 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725911AbgAWBlx (ORCPT ); Wed, 22 Jan 2020 20:41:53 -0500 X-IronPort-AV: E=Sophos;i="5.70,351,1574092800"; d="scan'208";a="82502321" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 23 Jan 2020 09:41:48 +0800 Received: from G08CNEXMBPEKD04.g08.fujitsu.local (unknown [10.167.33.201]) by cn.fujitsu.com (Postfix) with ESMTP id C100A50A9970; Thu, 23 Jan 2020 09:32:35 +0800 (CST) Received: from G08CNEXCHPEKD05.g08.fujitsu.local (10.167.33.203) by G08CNEXMBPEKD04.g08.fujitsu.local (10.167.33.201) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 23 Jan 2020 09:41:48 +0800 Received: from TEST.g08.fujitsu.local (10.167.226.147) by G08CNEXCHPEKD05.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Thu, 23 Jan 2020 09:41:47 +0800 From: Cao jin To: , , , CC: , , , , , Subject: [RFC PATCH 2/2] x86/acpi: Cleanup acpi_process_madt() Date: Thu, 23 Jan 2020 09:41:44 +0800 Message-ID: <20200123014144.19155-3-caoj.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200123014144.19155-1-caoj.fnst@cn.fujitsu.com> References: <20200123014144.19155-1-caoj.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: C100A50A9970.A8DA6 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: caoj.fnst@cn.fujitsu.com X-Spam-Status: No Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org After many duct-taped patches, the readablity of these code chunks are really hard. This patch does following improvements: 1. Drop unnecessary comment that is self-documented by function name, while supply with necessary comments. 2. Drop duplicated code: acpi_process_madt() has already been called in early madt processing, acpi_lapic & smp_found_config is also initialized there. 3. Fix code logic: variable count's usage is quite confusing now, and some code logic is wrong, like count & x2count will never be negative after assigned from madt_proc[n].count Signed-off-by: Cao jin --- arch/x86/kernel/acpi/boot.c | 44 +++++++++++++++---------------------- 1 file changed, 18 insertions(+), 26 deletions(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 2131035bba98..844fc9f26064 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1026,9 +1026,10 @@ static int __init early_acpi_parse_madt_lapic_addr_ovr(void) return count; } +/* Returns 0 on success, < 0 on error. */ static int __init acpi_parse_madt_lapic_entries(void) { - int count; + int count = 0; int x2count = 0; int ret; struct acpi_subtable_proc madt_proc[2]; @@ -1036,10 +1037,13 @@ static int __init acpi_parse_madt_lapic_entries(void) if (!boot_cpu_has(X86_FEATURE_APIC)) return -ENODEV; - count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_SAPIC, - acpi_parse_sapic, MAX_LOCAL_APIC); + /* SAPIC is commonly found on Intel Itanium processor. */ + ret = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_SAPIC, + acpi_parse_sapic, MAX_LOCAL_APIC); - if (!count) { + + /* No SAPIC entries implies it is not Itanium processor. */ + if (!ret) { memset(madt_proc, 0, sizeof(madt_proc)); madt_proc[0].id = ACPI_MADT_TYPE_LOCAL_APIC; madt_proc[0].handler = acpi_parse_lapic; @@ -1056,15 +1060,14 @@ static int __init acpi_parse_madt_lapic_entries(void) count = madt_proc[0].count; x2count = madt_proc[1].count; - } - if (!count && !x2count) { - printk(KERN_ERR PREFIX "No LAPIC entries present\n"); - /* TBD: Cleanup to allow fallback to MPS */ - return -ENODEV; - } else if (count < 0 || x2count < 0) { - printk(KERN_ERR PREFIX "Error parsing LAPIC entry\n"); - /* TBD: Cleanup to allow fallback to MPS */ - return count; + if (!count && !x2count) { + printk(KERN_ERR PREFIX "No LAPIC entries present\n"); + /* TBD: Cleanup to allow fallback to MPS */ + return -ENODEV; + } + } else if (ret < 0) { + printk(KERN_ERR PREFIX "Error parsing SAPIC entries\n"); + return ret; } x2count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_X2APIC_NMI, @@ -1074,7 +1077,7 @@ static int __init acpi_parse_madt_lapic_entries(void) if (count < 0 || x2count < 0) { printk(KERN_ERR PREFIX "Error parsing LAPIC NMI entry\n"); /* TBD: Cleanup to allow fallback to MPS */ - return count; + return (count < 0) ? count : x2count; } return 0; } @@ -1255,25 +1258,14 @@ static void __init acpi_process_madt(void) #ifdef CONFIG_X86_LOCAL_APIC int error; - if (!acpi_table_parse(ACPI_SIG_MADT, acpi_parse_madt)) { - - /* - * Parse MADT LAPIC entries - */ + if (acpi_lapic) { error = acpi_parse_madt_lapic_entries(); if (!error) { - acpi_lapic = 1; - - /* - * Parse MADT IO-APIC entries - */ mutex_lock(&acpi_ioapic_lock); error = acpi_parse_madt_ioapic_entries(); mutex_unlock(&acpi_ioapic_lock); if (!error) { acpi_set_irq_model_ioapic(); - - smp_found_config = 1; } } if (error == -EINVAL) {