PCI/ACPI: Protect acpi_pci_drivers list with mutex

Use mutex to protect global acpi_pci_drivers list against PCI
host bridge hotplug operations.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 4bec13d9c2bfc68529ca0fa2fe978a63ab9b315c..d710585e4a7fa4788ad25a6fb4435a2cffae799c 100644 (file)
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -27,7 +27,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/pci.h>
@@ -71,6 +71,8 @@ static struct acpi_driver acpi_pci_root_driver = {
                },
 };
 
+/* 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);
 
@@ -81,34 +83,30 @@ int acpi_pci_register_driver(struct acpi_pci_driver *driver)
        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(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(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)
@@ -628,9 +626,11 @@ static int acpi_pci_root_start(struct acpi_device *device)
        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);
+       mutex_unlock(&acpi_pci_root_lock);
 
        pci_bus_add_devices(root->bus);
 
@@ -642,9 +642,11 @@ static int acpi_pci_root_remove(struct acpi_device *device, int type)
        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);
+       mutex_unlock(&acpi_pci_root_lock);
 
        device_set_run_wake(root->bus->bridge, false);
        pci_acpi_remove_bus_pm_notifier(device);