PCI/ACPI: Protect acpi_pci_roots list with mutex

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

[bhelgaas: s/struct acpi_handle *handle/acpi_handle handle/]
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 18 insertions, 9 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 2868a9ff6d07..e1bdcc700cbb 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -112,12 +112,17 @@ EXPORT_SYMBOL(acpi_pci_unregister_driver);
 acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
 {
         struct acpi_pci_root *root;
+        acpi_handle handle = NULL;
         
+        mutex_lock(&acpi_pci_root_lock);
         list_for_each_entry(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;
+                }
+        mutex_unlock(&acpi_pci_root_lock);
+        return handle;
 }
 
 EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);
@@ -506,8 +511,9 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
          * TBD: Need PCI interface for enumeration/configuration of roots.
          */
 
-        /* TBD: Locking */
+        mutex_lock(&acpi_pci_root_lock);
         list_add_tail(&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 +532,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
                             "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 +542,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
          */
         result = acpi_pci_bind_root(device);
         if (result)
-                goto end;
+                goto out_del_root;
 
         /*
          * PCI Routing Table
@@ -614,9 +620,11 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 
         return 0;
 
+out_del_root:
+        mutex_lock(&acpi_pci_root_lock);
+        list_del(&root->node);
+        mutex_unlock(&acpi_pci_root_lock);
 end:
-        if (!list_empty(&root->node))
-                list_del(&root->node);
         kfree(root);
         return result;
 }
@@ -646,11 +654,12 @@ static int acpi_pci_root_remove(struct acpi_device *device, int type)
         list_for_each_entry(driver, &acpi_pci_drivers, node)
                 if (driver->remove)
                         driver->remove(root);
-        mutex_unlock(&acpi_pci_root_lock);
 
         device_set_run_wake(root->bus->bridge, false);
         pci_acpi_remove_bus_pm_notifier(device);
 
+        list_del(&root->node);
+        mutex_unlock(&acpi_pci_root_lock);
         kfree(root);
         return 0;
 }