Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932784AbaFQF2R (ORCPT ); Tue, 17 Jun 2014 01:28:17 -0400 Received: from mga01.intel.com ([192.55.52.88]:43830 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932750AbaFQF2N (ORCPT ); Tue, 17 Jun 2014 01:28:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,492,1400050800"; d="scan'208";a="549015314" From: Jiang Liu To: Benjamin Herrenschmidt , Thomas Gleixner , Grant Likely , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , Bjorn Helgaas , Randy Dunlap , Yinghai Lu , Len Brown , Pavel Machek , x86@kernel.org Cc: Jiang Liu , Konrad Rzeszutek Wilk , Andrew Morton , Tony Luck , Joerg Roedel , Paul Gortmaker , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org Subject: [RFC Patch V2 11/16] x86, irq, ACPI: introduce a rwsem to protect IOAPIC operations from hotplug Date: Tue, 17 Jun 2014 13:29:50 +0800 Message-Id: <1402982995-13747-12-git-send-email-jiang.liu@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1402982995-13747-1-git-send-email-jiang.liu@linux.intel.com> References: <1402982995-13747-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We are going to support ACPI based IOAPIC hotplug, so introduce a rwsem to protect IOAPIC data structures from IOAPIC hotplug. We choose to serialize in ACPI instead of in the IOAPIC core because: 1) currently we are only plan to support ACPI based IOAPIC hotplug 2) it's much more clean and easy 3) It does't affect IOAPIC discovered by devicetree, SFI and mppparse. Signed-off-by: Jiang Liu --- arch/x86/kernel/acpi/boot.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 8c28023924bf..120b573f1e96 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -76,6 +76,8 @@ int acpi_fix_pin2_polarity __initdata; static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; #endif +static DECLARE_RWSEM(acpi_ioapic_rwsem); + #ifndef __HAVE_ARCH_CMPXCHG #warning ACPI uses CMPXCHG, i486 and later hardware #endif @@ -608,8 +610,11 @@ void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger) int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp) { - int irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK); + int irq; + down_read(&acpi_ioapic_rwsem); + irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK); + up_read(&acpi_ioapic_rwsem); if (irq >= 0) { *irqp = irq; return 0; @@ -650,7 +655,9 @@ static int acpi_register_gsi_ioapic(struct device *dev, u32 gsi, int irq = gsi; #ifdef CONFIG_X86_IO_APIC + down_read(&acpi_ioapic_rwsem); irq = mp_register_gsi(dev, gsi, trigger, polarity); + up_read(&acpi_ioapic_rwsem); #endif return irq; @@ -659,7 +666,9 @@ static int acpi_register_gsi_ioapic(struct device *dev, u32 gsi, static void acpi_unregister_gsi_ioapic(u32 gsi) { #ifdef CONFIG_X86_IO_APIC + down_read(&acpi_ioapic_rwsem); mp_unregister_gsi(gsi); + up_read(&acpi_ioapic_rwsem); #endif } @@ -1185,7 +1194,9 @@ static void __init acpi_process_madt(void) /* * Parse MADT IO-APIC entries */ + down_write(&acpi_ioapic_rwsem); error = acpi_parse_madt_ioapic_entries(); + up_write(&acpi_ioapic_rwsem); if (!error) { acpi_set_irq_model_ioapic(); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/