From patchwork Mon Sep 3 08:06:02 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taku Izumi X-Patchwork-Id: 181310 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id D7EA52C0094 for ; Mon, 3 Sep 2012 18:05:53 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755080Ab2ICIFw (ORCPT ); Mon, 3 Sep 2012 04:05:52 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:58404 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755065Ab2ICIFv (ORCPT ); Mon, 3 Sep 2012 04:05:51 -0400 Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id D40413EE0B5; Mon, 3 Sep 2012 17:05:50 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id BB18245DE4D; Mon, 3 Sep 2012 17:05:50 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 9E9B745DE53; Mon, 3 Sep 2012 17:05:50 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 90AB11DB802C; Mon, 3 Sep 2012 17:05:50 +0900 (JST) Received: from m003.s.css.fujitsu.com (m003.s.css.fujitsu.com [10.23.4.33]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 4B8331DB803C; Mon, 3 Sep 2012 17:05:50 +0900 (JST) Received: from m003.css.fujitsu.com (m003 [127.0.0.1]) by m003.s.css.fujitsu.com (Postfix) with ESMTP id A7B7550EBFF; Mon, 3 Sep 2012 17:05:49 +0900 (JST) Received: from DEUCALION (unknown [10.124.101.32]) by m003.s.css.fujitsu.com (Postfix) with SMTP id AC7CA50EC2A; Mon, 3 Sep 2012 17:05:36 +0900 (JST) X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Date: Mon, 3 Sep 2012 17:06:02 +0900 From: Taku Izumi To: Taku Izumi Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, linux-acpi@vger.kernel.org, kaneshige.kenji@jp.fujitsu.com, yinghai@kernel.org, jiang.liu@huawei.com Subject: [PATCH v2 4/6] ACPI, PCI: add acpi_pci_roots protection Message-Id: <20120903170602.375b00cc.izumi.taku@jp.fujitsu.com> In-Reply-To: <20120903165831.29aed72c.izumi.taku@jp.fujitsu.com> References: <20120903165831.29aed72c.izumi.taku@jp.fujitsu.com> X-Mailer: Sylpheed 3.1.1 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Use mutex and RCU to protect global acpi_pci_roots list against PCI host bridge hotplug operations. RCU is used to avoid possible deadlock in function acpi_pci_find_root() and acpi_get_pci_rootbridge_handle(). A possible call graph: acpi_pci_register_driver() mutex_lock(&acpi_pci_root_lock) driver->add(root) ...... acpi_pci_find_root() Signed-off-by: Jiang Liu Signed-off-by: Yinghai Lu Signed-off-by: Taku Izumi --- drivers/acpi/pci_root.c | 50 +++++++++++++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 17 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: Bjorn-next-0903/drivers/acpi/pci_root.c =================================================================== --- Bjorn-next-0903.orig/drivers/acpi/pci_root.c +++ Bjorn-next-0903/drivers/acpi/pci_root.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -86,7 +87,7 @@ int acpi_pci_register_driver(struct acpi mutex_lock(&acpi_pci_root_lock); list_add_tail(&driver->node, &acpi_pci_drivers); if (driver->add) - list_for_each_entry(root, &acpi_pci_roots, node) { + list_for_each_entry_rcu(root, &acpi_pci_roots, node) { driver->add(root->device->handle); n++; } @@ -103,7 +104,7 @@ void acpi_pci_unregister_driver(struct a mutex_lock(&acpi_pci_root_lock); list_del(&driver->node); if (driver->remove) - list_for_each_entry(root, &acpi_pci_roots, node) + list_for_each_entry_rcu(root, &acpi_pci_roots, node) driver->remove(root->device->handle); mutex_unlock(&acpi_pci_root_lock); } @@ -112,14 +113,19 @@ EXPORT_SYMBOL(acpi_pci_unregister_driver acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus) { struct acpi_pci_root *root; + struct acpi_handle *handle = NULL; - list_for_each_entry(root, &acpi_pci_roots, node) + rcu_read_lock(); + list_for_each_entry_rcu(root, &acpi_pci_roots, node) if ((root->segment == (u16) seg) && - (root->secondary.start == (u16) bus)) - return root->device->handle; - return NULL; -} + (root->secondary.start == (u16) bus)) { + handle = root->device->handle; + break; + } + rcu_read_unlock(); + return handle; +} EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle); /** @@ -266,10 +272,14 @@ struct acpi_pci_root *acpi_pci_find_root { struct acpi_pci_root *root; - list_for_each_entry(root, &acpi_pci_roots, node) { - if (root->device->handle == handle) + rcu_read_lock(); + list_for_each_entry_rcu(root, &acpi_pci_roots, node) + if (root->device->handle == handle) { + rcu_read_unlock(); return root; - } + } + rcu_read_unlock(); + return NULL; } EXPORT_SYMBOL_GPL(acpi_pci_find_root); @@ -506,8 +516,9 @@ static int __devinit acpi_pci_root_add(s * TBD: Need PCI interface for enumeration/configuration of roots. */ - /* TBD: Locking */ - list_add_tail(&root->node, &acpi_pci_roots); + mutex_lock(&acpi_pci_root_lock); + list_add_tail_rcu(&root->node, &acpi_pci_roots); + mutex_unlock(&acpi_pci_root_lock); printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n", acpi_device_name(device), acpi_device_bid(device), @@ -526,7 +537,7 @@ static int __devinit acpi_pci_root_add(s "Bus %04x:%02x not present in PCI namespace\n", root->segment, (unsigned int)root->secondary.start); result = -ENODEV; - goto end; + goto out_del_root; } /* @@ -536,7 +547,7 @@ static int __devinit acpi_pci_root_add(s */ result = acpi_pci_bind_root(device); if (result) - goto end; + goto out_del_root; /* * PCI Routing Table @@ -614,9 +625,12 @@ static int __devinit acpi_pci_root_add(s return 0; +out_del_root: + mutex_lock(&acpi_pci_root_lock); + list_del_rcu(&root->node); + mutex_unlock(&acpi_pci_root_lock); + synchronize_rcu(); end: - if (!list_empty(&root->node)) - list_del(&root->node); kfree(root); return result; } @@ -646,11 +660,13 @@ static int acpi_pci_root_remove(struct a list_for_each_entry(driver, &acpi_pci_drivers, node) if (driver->remove) driver->remove(root->device->handle); - mutex_unlock(&acpi_pci_root_lock); device_set_run_wake(root->bus->bridge, false); pci_acpi_remove_bus_pm_notifier(device); + list_del_rcu(&root->node); + mutex_unlock(&acpi_pci_root_lock); + synchronize_rcu(); kfree(root); return 0; }