Merge branch 'acpi-hotplug'

* acpi-hotplug:
  ACPI / hotplug: Remove containers synchronously
  driver core / ACPI: Avoid device hot remove locking issues

3 files changed, 46 insertions, 50 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e76365136ba3..61d090b6ce25 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -287,6 +287,7 @@ static void acpi_bus_device_eject(void *context)
 	struct acpi_device *device = NULL;
 	struct acpi_scan_handler *handler;
 	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+	int error;
 
 	mutex_lock(&acpi_scan_lock);
 
@@ -301,17 +302,13 @@ static void acpi_bus_device_eject(void *context)
 	}
 	acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
 				  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
-	if (handler->hotplug.mode == AHM_CONTAINER) {
-		device->flags.eject_pending = true;
+	if (handler->hotplug.mode == AHM_CONTAINER)
 		kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
-	} else {
-		int error;
 
-		get_device(&device->dev);
-		error = acpi_scan_hot_remove(device);
-		if (error)
-			goto err_out;
-	}
+	get_device(&device->dev);
+	error = acpi_scan_hot_remove(device);
+	if (error)
+		goto err_out;
 
  out:
 	mutex_unlock(&acpi_scan_lock);
@@ -496,7 +493,6 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
 	struct acpi_eject_event *ej_event;
 	acpi_object_type not_used;
 	acpi_status status;
-	u32 ost_source;
 	int ret;
 
 	if (!count || buf[0] != '1')
@@ -510,43 +506,28 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
 	if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
 		return -ENODEV;
 
-	mutex_lock(&acpi_scan_lock);
-
-	if (acpi_device->flags.eject_pending) {
-		/* ACPI eject notification event. */
-		ost_source = ACPI_NOTIFY_EJECT_REQUEST;
-		acpi_device->flags.eject_pending = 0;
-	} else {
-		/* Eject initiated by user space. */
-		ost_source = ACPI_OST_EC_OSPM_EJECT;
-	}
 	ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
 	if (!ej_event) {
 		ret = -ENOMEM;
 		goto err_out;
 	}
-	acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+	acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
 				  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
 	ej_event->device = acpi_device;
-	ej_event->event = ost_source;
+	ej_event->event = ACPI_OST_EC_OSPM_EJECT;
 	get_device(&acpi_device->dev);
 	status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
-	if (ACPI_FAILURE(status)) {
-		put_device(&acpi_device->dev);
-		kfree(ej_event);
-		ret = status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
-		goto err_out;
-	}
-	ret = count;
+	if (ACPI_SUCCESS(status))
+		return count;
 
- out:
-	mutex_unlock(&acpi_scan_lock);
-	return ret;
+	put_device(&acpi_device->dev);
+	kfree(ej_event);
+	ret = status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
 
  err_out:
-	acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+	acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
 				  ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
-	goto out;
+	return ret;
 }
 
 static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8856d74545d9..ac419a15fcd4 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -49,6 +49,28 @@ static struct kobject *dev_kobj;
 struct kobject *sysfs_dev_char_kobj;
 struct kobject *sysfs_dev_block_kobj;
 
+static DEFINE_MUTEX(device_hotplug_lock);
+
+void lock_device_hotplug(void)
+{
+	mutex_lock(&device_hotplug_lock);
+}
+
+void unlock_device_hotplug(void)
+{
+	mutex_unlock(&device_hotplug_lock);
+}
+
+int lock_device_hotplug_sysfs(void)
+{
+	if (mutex_trylock(&device_hotplug_lock))
+		return 0;
+
+	/* Avoid busy looping (5 ms of sleep should do). */
+	msleep(5);
+	return restart_syscall();
+}
+
 #ifdef CONFIG_BLOCK
 static inline int device_is_not_partition(struct device *dev)
 {
@@ -408,9 +430,9 @@ static ssize_t show_online(struct device *dev, struct device_attribute *attr,
 {
 	bool val;
 
-	lock_device_hotplug();
+	device_lock(dev);
 	val = !dev->offline;
-	unlock_device_hotplug();
+	device_unlock(dev);
 	return sprintf(buf, "%u\n", val);
 }
 
@@ -424,7 +446,10 @@ static ssize_t store_online(struct device *dev, struct device_attribute *attr,
 	if (ret < 0)
 		return ret;
 
-	lock_device_hotplug();
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
+
 	ret = val ? device_online(dev) : device_offline(dev);
 	unlock_device_hotplug();
 	return ret < 0 ? ret : count;
@@ -1479,18 +1504,6 @@ EXPORT_SYMBOL_GPL(put_device);
 EXPORT_SYMBOL_GPL(device_create_file);
 EXPORT_SYMBOL_GPL(device_remove_file);
 
-static DEFINE_MUTEX(device_hotplug_lock);
-
-void lock_device_hotplug(void)
-{
-	mutex_lock(&device_hotplug_lock);
-}
-
-void unlock_device_hotplug(void)
-{
-	mutex_unlock(&device_hotplug_lock);
-}
-
 static int device_check_offline(struct device *dev, void *not_used)
 {
 	int ret;
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 2b7813ec6d02..6f4c99ff1ce7 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -351,7 +351,9 @@ store_mem_state(struct device *dev,
 
 	mem = container_of(dev, struct memory_block, dev);
 
-	lock_device_hotplug();
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
 
 	if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) {
 		offline = false;