From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:40429 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754452Ab2HJGOX (ORCPT ); Fri, 10 Aug 2012 02:14:23 -0400 Date: Fri, 10 Aug 2012 15:14:17 +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 5/7][RESEND] ACPI, PCI: Protect global lists in drivers/acpi/pci_root.c Message-Id: <20120810151417.031666ce.izumi.taku@jp.fujitsu.com> In-Reply-To: <20120810150955.e4ab3c7f.izumi.taku@jp.fujitsu.com> References: <20120810150955.e4ab3c7f.izumi.taku@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-pci-owner@vger.kernel.org List-ID: From: Jiang Liu ACPI, PCI: Protect global lists in drivers/acpi/pci_root.c There are two global lists inf file drivers/acpi/pci_root.c. One is for registered acpi_pci_drivers, the other is for enumerated ACPI PCI root bridge objects. These two global lists may change dynamically when registering/deregistering acpi_pci_drivers or adding/removing ACPI PCI root bridge objects. So protect them by mutex lock and RCU list. Signed-off-by: Jiang Liu Signed-off-by: Yinghai Lu [izumi.taku@jp.fujitsu.com: a bit change at acpi_pci_root_remove()] Signed-off-by: Taku Izumi --- drivers/acpi/pci_root.c | 86 +++++++++++++++++++++++++++++------------------- 1 file changed, 53 insertions(+), 33 deletions(-) Index: Bjorn-next/drivers/acpi/pci_root.c =================================================================== --- Bjorn-next.orig/drivers/acpi/pci_root.c +++ Bjorn-next/drivers/acpi/pci_root.c @@ -27,7 +27,8 @@ #include #include #include -#include +#include +#include #include #include #include @@ -71,6 +72,8 @@ static struct acpi_driver acpi_pci_root_ }, }; +/* Lock to protect both acpi_pci_roots and acpi_pci_drivers lists */ +static DEFINE_MUTEX(acpi_pci_root_lock); static LIST_HEAD(acpi_pci_roots); static LIST_HEAD(acpi_pci_drivers); @@ -81,47 +84,48 @@ int acpi_pci_register_driver(struct acpi int n = 0; struct acpi_pci_root *root; + mutex_lock(&acpi_pci_root_lock); list_add_tail(&driver->node, &acpi_pci_drivers); - - if (!driver->add) - return 0; - - list_for_each_entry(root, &acpi_pci_roots, node) { - driver->add(root->device->handle); - n++; - } + if (driver->add) + list_for_each_entry_rcu(root, &acpi_pci_roots, node) { + driver->add(root->device->handle); + n++; + } + mutex_unlock(&acpi_pci_root_lock); return n; } - EXPORT_SYMBOL(acpi_pci_register_driver); void acpi_pci_unregister_driver(struct acpi_pci_driver *driver) { struct acpi_pci_root *root; + mutex_lock(&acpi_pci_root_lock); list_del(&driver->node); - - if (!driver->remove) - return; - - list_for_each_entry(root, &acpi_pci_roots, node) - driver->remove(root->device->handle); + if (driver->remove) + list_for_each_entry_rcu(root, &acpi_pci_roots, node) + driver->remove(root->device->handle); + mutex_unlock(&acpi_pci_root_lock); } - 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); /** @@ -268,10 +272,15 @@ 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); @@ -459,7 +468,7 @@ static int __devinit acpi_pci_root_add(s if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) { printk(KERN_ERR PREFIX "can't evaluate _SEG\n"); result = -ENODEV; - goto end; + goto out_free; } /* Check _CRS first, then _BBN. If no _BBN, default to zero. */ @@ -484,7 +493,7 @@ static int __devinit acpi_pci_root_add(s else { printk(KERN_ERR PREFIX "can't evaluate _BBN\n"); result = -ENODEV; - goto end; + goto out_free; } } @@ -508,8 +517,8 @@ 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); printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n", acpi_device_name(device), acpi_device_bid(device), @@ -528,7 +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; } /* @@ -538,7 +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 @@ -614,11 +623,15 @@ static int __devinit acpi_pci_root_add(s if (device->wakeup.flags.run_wake) device_set_run_wake(root->bus->bridge, true); + mutex_unlock(&acpi_pci_root_lock); + return 0; -end: - if (!list_empty(&root->node)) - list_del(&root->node); +out_del_root: + list_del_rcu(&root->node); + mutex_unlock(&acpi_pci_root_lock); + synchronize_rcu(); +out_free: kfree(root); return result; } @@ -628,11 +641,13 @@ static int acpi_pci_root_start(struct ac struct acpi_pci_root *root = acpi_driver_data(device); struct acpi_pci_driver *driver; + mutex_lock(&acpi_pci_root_lock); list_for_each_entry(driver, &acpi_pci_drivers, node) if (driver->add) driver->add(device->handle); pci_bus_add_devices(root->bus); + mutex_unlock(&acpi_pci_root_lock); return 0; } @@ -642,6 +657,8 @@ static int acpi_pci_root_remove(struct a struct acpi_pci_root *root = acpi_driver_data(device); struct acpi_pci_driver *driver; + mutex_lock(&acpi_pci_root_lock); + list_for_each_entry(driver, &acpi_pci_drivers, node) if (driver->remove) driver->remove(root->device->handle); @@ -649,6 +666,9 @@ static int acpi_pci_root_remove(struct a 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; }