3 files changed, 117 insertions, 0 deletions

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 6f1afd9118c8..4548f0a114ce 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -47,6 +47,8 @@ void acpi_memory_hotplug_init(void);
 static inline void acpi_memory_hotplug_init(void) {}
 #endif
 
+extern bool acpi_force_hot_remove;
+
 void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug,
                                     const char *name);
 int acpi_scan_add_handler_with_hotplug(struct acpi_scan_handler *handler,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index fe158fd4f1df..4fd392005ef1 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -27,6 +27,12 @@ extern struct acpi_device *acpi_root;
 
 #define ACPI_IS_ROOT_DEVICE(device)    (!(device)->parent)
 
+/*
+ * If set, devices will be hot-removed even if they cannot be put offline
+ * gracefully (from the kernel's standpoint).
+ */
+bool acpi_force_hot_remove;
+
 static const char *dummy_hid = "device";
 
 static LIST_HEAD(acpi_device_list);
@@ -120,6 +126,59 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
 }
 static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
 
+static acpi_status acpi_bus_offline_companions(acpi_handle handle, u32 lvl,
+                                               void *data, void **ret_p)
+{
+        struct acpi_device *device = NULL;
+        struct acpi_device_physical_node *pn;
+        acpi_status status = AE_OK;
+
+        if (acpi_bus_get_device(handle, &device))
+                return AE_OK;
+
+        mutex_lock(&device->physical_node_lock);
+
+        list_for_each_entry(pn, &device->physical_node_list, node) {
+                int ret;
+
+                ret = device_offline(pn->dev);
+                if (acpi_force_hot_remove)
+                        continue;
+
+                if (ret < 0) {
+                        status = AE_ERROR;
+                        break;
+                }
+                pn->put_online = !ret;
+        }
+
+        mutex_unlock(&device->physical_node_lock);
+
+        return status;
+}
+
+static acpi_status acpi_bus_online_companions(acpi_handle handle, u32 lvl,
+                                              void *data, void **ret_p)
+{
+        struct acpi_device *device = NULL;
+        struct acpi_device_physical_node *pn;
+
+        if (acpi_bus_get_device(handle, &device))
+                return AE_OK;
+
+        mutex_lock(&device->physical_node_lock);
+
+        list_for_each_entry(pn, &device->physical_node_list, node)
+                if (pn->put_online) {
+                        device_online(pn->dev);
+                        pn->put_online = false;
+                }
+
+        mutex_unlock(&device->physical_node_lock);
+
+        return AE_OK;
+}
+
 static int acpi_scan_hot_remove(struct acpi_device *device)
 {
         acpi_handle handle = device->handle;
@@ -136,10 +195,33 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
                 return -EINVAL;
         }
 
+        lock_device_hotplug();
+
+        status = acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+                                     NULL, acpi_bus_offline_companions, NULL,
+                                     NULL);
+        if (ACPI_SUCCESS(status) || acpi_force_hot_remove)
+                status = acpi_bus_offline_companions(handle, 0, NULL, NULL);
+
+        if (ACPI_FAILURE(status) && !acpi_force_hot_remove) {
+                acpi_bus_online_companions(handle, 0, NULL, NULL);
+                acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+                                    acpi_bus_online_companions, NULL, NULL,
+                                    NULL);
+
+                unlock_device_hotplug();
+
+                put_device(&device->dev);
+                return -EBUSY;
+        }
+
         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                 "Hot-removing device %s...\n", dev_name(&device->dev)));
 
         acpi_bus_trim(device);
+
+        unlock_device_hotplug();
+
         /* Device node has been unregistered. */
         put_device(&device->dev);
         device = NULL;
@@ -236,6 +318,7 @@ static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
         int error;
 
         mutex_lock(&acpi_scan_lock);
+        lock_device_hotplug();
 
         acpi_bus_get_device(handle, &device);
         if (device) {
@@ -259,6 +342,7 @@ static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
                 kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);
 
  out:
+        unlock_device_hotplug();
         acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
         mutex_unlock(&acpi_scan_lock);
 }
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index fcae5fa2e1b3..5c5d1624fa2c 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -780,6 +780,33 @@ void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug,
         pr_err(PREFIX "Unable to add hotplug profile '%s'\n", name);
 }
 
+static ssize_t force_remove_show(struct kobject *kobj,
+                                 struct kobj_attribute *attr, char *buf)
+{
+        return sprintf(buf, "%d\n", !!acpi_force_hot_remove);
+}
+
+static ssize_t force_remove_store(struct kobject *kobj,
+                                  struct kobj_attribute *attr,
+                                  const char *buf, size_t size)
+{
+        bool val;
+        int ret;
+
+        ret = strtobool(buf, &val);
+        if (ret < 0)
+                return ret;
+
+        lock_device_hotplug();
+        acpi_force_hot_remove = val;
+        unlock_device_hotplug();
+        return size;
+}
+
+static const struct kobj_attribute force_remove_attr =
+        __ATTR(force_remove, S_IRUGO | S_IWUSR, force_remove_show,
+               force_remove_store);
+
 int __init acpi_sysfs_init(void)
 {
         int result;
@@ -789,6 +816,10 @@ int __init acpi_sysfs_init(void)
                 return result;
 
         hotplug_kobj = kobject_create_and_add("hotplug", acpi_kobj);
+        result = sysfs_create_file(hotplug_kobj, &force_remove_attr.attr);
+        if (result)
+                return result;
+
         result = sysfs_create_file(acpi_kobj, &pm_profile_attr.attr);
         return result;
 }