1 files changed, 206 insertions, 99 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 0c916c18a250..57507b643afd 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -49,12 +49,6 @@ static DEFINE_MUTEX(acpi_hp_context_lock);
  */
 static u64 spcr_uart_addr;
 
-struct acpi_dep_data {
-	struct list_head node;
-	acpi_handle supplier;
-	acpi_handle consumer;
-};
-
 void acpi_scan_lock_acquire(void)
 {
 	mutex_lock(&acpi_scan_lock);
@@ -614,11 +608,6 @@ struct acpi_device *acpi_bus_get_acpi_device(acpi_handle handle)
 	return handle_to_device(handle, get_acpi_device);
 }
 
-void acpi_bus_put_acpi_device(struct acpi_device *adev)
-{
-	acpi_dev_put(adev);
-}
-
 static struct acpi_device_bus_id *acpi_device_bus_id_match(const char *dev_id)
 {
 	struct acpi_device_bus_id *acpi_device_bus_id;
@@ -646,24 +635,29 @@ static int acpi_device_set_name(struct acpi_device *device,
 	return 0;
 }
 
-int acpi_device_add(struct acpi_device *device,
-		    void (*release)(struct device *))
+static int acpi_tie_acpi_dev(struct acpi_device *adev)
 {
-	struct acpi_device_bus_id *acpi_device_bus_id;
-	int result;
+	acpi_handle handle = adev->handle;
+	acpi_status status;
 
-	if (device->handle) {
-		acpi_status status;
+	if (!handle)
+		return 0;
 
-		status = acpi_attach_data(device->handle, acpi_scan_drop_device,
-					  device);
-		if (ACPI_FAILURE(status)) {
-			acpi_handle_err(device->handle,
-					"Unable to attach device data\n");
-			return -ENODEV;
-		}
+	status = acpi_attach_data(handle, acpi_scan_drop_device, adev);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "Unable to attach device data\n");
+		return -ENODEV;
 	}
 
+	return 0;
+}
+
+static int __acpi_device_add(struct acpi_device *device,
+			     void (*release)(struct device *))
+{
+	struct acpi_device_bus_id *acpi_device_bus_id;
+	int result;
+
 	/*
 	 * Linkage
 	 * -------
@@ -752,6 +746,17 @@ err_unlock:
 	return result;
 }
 
+int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *))
+{
+	int ret;
+
+	ret = acpi_tie_acpi_dev(adev);
+	if (ret)
+		return ret;
+
+	return __acpi_device_add(adev, release);
+}
+
 /* --------------------------------------------------------------------------
                                  Device Enumeration
    -------------------------------------------------------------------------- */
@@ -1672,8 +1677,16 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
 	device_initialize(&device->dev);
 	dev_set_uevent_suppress(&device->dev, true);
 	acpi_init_coherency(device);
-	/* Assume there are unmet deps to start with. */
-	device->dep_unmet = 1;
+}
+
+static void acpi_scan_dep_init(struct acpi_device *adev)
+{
+	struct acpi_dep_data *dep;
+
+	list_for_each_entry(dep, &acpi_dep_list, node) {
+		if (dep->consumer == adev->handle)
+			adev->dep_unmet++;
+	}
 }
 
 void acpi_device_add_finalize(struct acpi_device *device)
@@ -1689,9 +1702,10 @@ static void acpi_scan_init_status(struct acpi_device *adev)
 }
 
 static int acpi_add_single_object(struct acpi_device **child,
-				  acpi_handle handle, int type)
+				  acpi_handle handle, int type, bool dep_init)
 {
 	struct acpi_device *device;
+	bool release_dep_lock = false;
 	int result;
 
 	device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
@@ -1704,13 +1718,32 @@ static int acpi_add_single_object(struct acpi_device **child,
 	 * acpi_bus_get_status() and use its quirk handling.  Note that
 	 * this must be done before the get power-/wakeup_dev-flags calls.
 	 */
-	if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR)
+	if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
+		if (dep_init) {
+			mutex_lock(&acpi_dep_list_lock);
+			/*
+			 * Hold the lock until the acpi_tie_acpi_dev() call
+			 * below to prevent concurrent acpi_scan_clear_dep()
+			 * from deleting a dependency list entry without
+			 * updating dep_unmet for the device.
+			 */
+			release_dep_lock = true;
+			acpi_scan_dep_init(device);
+		}
 		acpi_scan_init_status(device);
+	}
 
 	acpi_bus_get_power_flags(device);
 	acpi_bus_get_wakeup_device_flags(device);
 
-	result = acpi_device_add(device, acpi_device_release);
+	result = acpi_tie_acpi_dev(device);
+
+	if (release_dep_lock)
+		mutex_unlock(&acpi_dep_list_lock);
+
+	if (!result)
+		result = __acpi_device_add(device, acpi_device_release);
+
 	if (result) {
 		acpi_device_release(&device->dev);
 		return result;
@@ -1887,22 +1920,6 @@ static u32 acpi_scan_check_dep(acpi_handle handle, bool check_dep)
 	return count;
 }
 
-static void acpi_scan_dep_init(struct acpi_device *adev)
-{
-	struct acpi_dep_data *dep;
-
-	adev->dep_unmet = 0;
-
-	mutex_lock(&acpi_dep_list_lock);
-
-	list_for_each_entry(dep, &acpi_dep_list, node) {
-		if (dep->consumer == adev->handle)
-			adev->dep_unmet++;
-	}
-
-	mutex_unlock(&acpi_dep_list_lock);
-}
-
 static bool acpi_bus_scan_second_pass;
 
 static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,
@@ -1950,19 +1967,15 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,
 		return AE_OK;
 	}
 
-	acpi_add_single_object(&device, handle, type);
-	if (!device)
-		return AE_CTRL_DEPTH;
-
-	acpi_scan_init_hotplug(device);
 	/*
 	 * If check_dep is true at this point, the device has no dependencies,
 	 * or the creation of the device object would have been postponed above.
 	 */
-	if (check_dep)
-		device->dep_unmet = 0;
-	else
-		acpi_scan_dep_init(device);
+	acpi_add_single_object(&device, handle, type, !check_dep);
+	if (!device)
+		return AE_CTRL_DEPTH;
+
+	acpi_scan_init_hotplug(device);
 
 out:
 	if (!*adev_p)
@@ -2112,29 +2125,141 @@ static void acpi_bus_attach(struct acpi_device *device, bool first_pass)
 		device->handler->hotplug.notify_online(device);
 }
 
-void acpi_walk_dep_device_list(acpi_handle handle)
+static int acpi_dev_get_first_consumer_dev_cb(struct acpi_dep_data *dep, void *data)
 {
-	struct acpi_dep_data *dep, *tmp;
 	struct acpi_device *adev;
 
+	adev = acpi_bus_get_acpi_device(dep->consumer);
+	if (adev) {
+		*(struct acpi_device **)data = adev;
+		return 1;
+	}
+	/* Continue parsing if the device object is not present. */
+	return 0;
+}
+
+struct acpi_scan_clear_dep_work {
+	struct work_struct work;
+	struct acpi_device *adev;
+};
+
+static void acpi_scan_clear_dep_fn(struct work_struct *work)
+{
+	struct acpi_scan_clear_dep_work *cdw;
+
+	cdw = container_of(work, struct acpi_scan_clear_dep_work, work);
+
+	acpi_scan_lock_acquire();
+	acpi_bus_attach(cdw->adev, true);
+	acpi_scan_lock_release();
+
+	acpi_dev_put(cdw->adev);
+	kfree(cdw);
+}
+
+static bool acpi_scan_clear_dep_queue(struct acpi_device *adev)
+{
+	struct acpi_scan_clear_dep_work *cdw;
+
+	if (adev->dep_unmet)
+		return false;
+
+	cdw = kmalloc(sizeof(*cdw), GFP_KERNEL);
+	if (!cdw)
+		return false;
+
+	cdw->adev = adev;
+	INIT_WORK(&cdw->work, acpi_scan_clear_dep_fn);
+	/*
+	 * Since the work function may block on the lock until the entire
+	 * initial enumeration of devices is complete, put it into the unbound
+	 * workqueue.
+	 */
+	queue_work(system_unbound_wq, &cdw->work);
+
+	return true;
+}
+
+static int acpi_scan_clear_dep(struct acpi_dep_data *dep, void *data)
+{
+	struct acpi_device *adev = acpi_bus_get_acpi_device(dep->consumer);
+
+	if (adev) {
+		adev->dep_unmet--;
+		if (!acpi_scan_clear_dep_queue(adev))
+			acpi_dev_put(adev);
+	}
+
+	list_del(&dep->node);
+	kfree(dep);
+
+	return 0;
+}
+
+/**
+ * acpi_walk_dep_device_list - Apply a callback to every entry in acpi_dep_list
+ * @handle:	The ACPI handle of the supplier device
+ * @callback:	Pointer to the callback function to apply
+ * @data:	Pointer to some data to pass to the callback
+ *
+ * The return value of the callback determines this function's behaviour. If 0
+ * is returned we continue to iterate over acpi_dep_list. If a positive value
+ * is returned then the loop is broken but this function returns 0. If a
+ * negative value is returned by the callback then the loop is broken and that
+ * value is returned as the final error.
+ */
+static int acpi_walk_dep_device_list(acpi_handle handle,
+				int (*callback)(struct acpi_dep_data *, void *),
+				void *data)
+{
+	struct acpi_dep_data *dep, *tmp;
+	int ret = 0;
+
 	mutex_lock(&acpi_dep_list_lock);
 	list_for_each_entry_safe(dep, tmp, &acpi_dep_list, node) {
 		if (dep->supplier == handle) {
-			acpi_bus_get_device(dep->consumer, &adev);
-
-			if (adev) {
-				adev->dep_unmet--;
-				if (!adev->dep_unmet)
-					acpi_bus_attach(adev, true);
-			}
-
-			list_del(&dep->node);
-			kfree(dep);
+			ret = callback(dep, data);
+			if (ret)
+				break;
 		}
 	}
 	mutex_unlock(&acpi_dep_list_lock);
+
+	return ret > 0 ? 0 : ret;
+}
+
+/**
+ * acpi_dev_clear_dependencies - Inform consumers that the device is now active
+ * @supplier: Pointer to the supplier &struct acpi_device
+ *
+ * Clear dependencies on the given device.
+ */
+void acpi_dev_clear_dependencies(struct acpi_device *supplier)
+{
+	acpi_walk_dep_device_list(supplier->handle, acpi_scan_clear_dep, NULL);
+}
+EXPORT_SYMBOL_GPL(acpi_dev_clear_dependencies);
+
+/**
+ * acpi_dev_get_first_consumer_dev - Return ACPI device dependent on @supplier
+ * @supplier: Pointer to the dependee device
+ *
+ * Returns the first &struct acpi_device which declares itself dependent on
+ * @supplier via the _DEP buffer, parsed from the acpi_dep_list.
+ *
+ * The caller is responsible for putting the reference to adev when it is no
+ * longer needed.
+ */
+struct acpi_device *acpi_dev_get_first_consumer_dev(struct acpi_device *supplier)
+{
+	struct acpi_device *adev = NULL;
+
+	acpi_walk_dep_device_list(supplier->handle,
+				  acpi_dev_get_first_consumer_dev_cb, &adev);
+
+	return adev;
 }
-EXPORT_SYMBOL_GPL(acpi_walk_dep_device_list);
+EXPORT_SYMBOL_GPL(acpi_dev_get_first_consumer_dev);
 
 /**
  * acpi_bus_scan - Add ACPI device node objects in a given namespace scope.
@@ -2224,7 +2349,7 @@ int acpi_bus_register_early_device(int type)
 	struct acpi_device *device = NULL;
 	int result;
 
-	result = acpi_add_single_object(&device, NULL, type);
+	result = acpi_add_single_object(&device, NULL, type, false);
 	if (result)
 		return result;
 
@@ -2244,7 +2369,7 @@ static int acpi_bus_scan_fixed(void)
 		struct acpi_device *device = NULL;
 
 		result = acpi_add_single_object(&device, NULL,
-						ACPI_BUS_TYPE_POWER_BUTTON);
+						ACPI_BUS_TYPE_POWER_BUTTON, false);
 		if (result)
 			return result;
 
@@ -2260,7 +2385,7 @@ static int acpi_bus_scan_fixed(void)
 		struct acpi_device *device = NULL;
 
 		result = acpi_add_single_object(&device, NULL,
-						ACPI_BUS_TYPE_SLEEP_BUTTON);
+						ACPI_BUS_TYPE_SLEEP_BUTTON, false);
 		if (result)
 			return result;
 
@@ -2361,7 +2486,7 @@ int __init acpi_scan_init(void)
 		}
 	}
 
-	acpi_turn_off_unused_power_resources(true);
+	acpi_turn_off_unused_power_resources();
 
 	acpi_scan_initialized = true;
 
@@ -2409,46 +2534,28 @@ int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr)
 	return count;
 }
 
-struct acpi_table_events_work {
-	struct work_struct work;
-	void *table;
-	u32 event;
-};
-
 static void acpi_table_events_fn(struct work_struct *work)
 {
-	struct acpi_table_events_work *tew;
+	acpi_scan_lock_acquire();
+	acpi_bus_scan(ACPI_ROOT_OBJECT);
+	acpi_scan_lock_release();
 
-	tew = container_of(work, struct acpi_table_events_work, work);
-
-	if (tew->event == ACPI_TABLE_EVENT_LOAD) {
-		acpi_scan_lock_acquire();
-		acpi_bus_scan(ACPI_ROOT_OBJECT);
-		acpi_scan_lock_release();
-	}
-
-	kfree(tew);
+	kfree(work);
 }
 
-void acpi_scan_table_handler(u32 event, void *table, void *context)
+void acpi_scan_table_notify(void)
 {
-	struct acpi_table_events_work *tew;
+	struct work_struct *work;
 
 	if (!acpi_scan_initialized)
 		return;
 
-	if (event != ACPI_TABLE_EVENT_LOAD)
-		return;
-
-	tew = kmalloc(sizeof(*tew), GFP_KERNEL);
-	if (!tew)
+	work = kmalloc(sizeof(*work), GFP_KERNEL);
+	if (!work)
 		return;
 
-	INIT_WORK(&tew->work, acpi_table_events_fn);
-	tew->table = table;
-	tew->event = event;
-
-	schedule_work(&tew->work);
+	INIT_WORK(work, acpi_table_events_fn);
+	schedule_work(work);
 }
 
 int acpi_reconfig_notifier_register(struct notifier_block *nb)