[RFC PATCH v3 17/28] ACPIHP: block ACPI device driver unloading when executing hotplug operations

[Jiang Liu <liuj97@gmail.com>]

The ACPI hotplug driver depends on ACPI device drivers to configure or
unconfigure ACPI devices. It will confuse the hotplug driver if an ACPI
device driver is unloaded when there are ongoing hotplug operations.
So block ACPI device driver unbinding/unloading by holding the device
lock when there are ongoing hotplug operations.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 drivers/acpi/hotplug/configure.c |   18 ++++++++++++++++--
 drivers/acpi/hotplug/device.c    |    8 --------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/hotplug/configure.c b/drivers/acpi/hotplug/configure.c
index 346b976..75e8752 100644
--- a/drivers/acpi/hotplug/configure.c
+++ b/drivers/acpi/hotplug/configure.c
@@ -37,7 +37,9 @@ enum config_op_code {
 	DRV_OP_POST_RELEASE,
 	DRV_OP_PRE_UNCONFIGURE,
 	DRV_OP_UNCONFIGURE,
-	DRV_OP_POST_UNCONFIGURE
+	DRV_OP_POST_UNCONFIGURE,
+	DRV_OP_LOCK_DEVICE,
+	DRV_OP_UNLOCK_DEVICE,
 };
 
 /* All devices will be configured in following order. */
@@ -102,6 +104,12 @@ static int acpihp_drv_invoke_method(enum config_op_code  opcode,
 		return acpihp_dev_unconfigure(dev);
 	case DRV_OP_POST_UNCONFIGURE:
 		return acpihp_dev_post_unconfigure(dev);
+	case DRV_OP_LOCK_DEVICE:
+		device_lock(&dev->dev);
+		return 0;
+	case DRV_OP_UNLOCK_DEVICE:
+		device_unlock(&dev->dev);
+		return 0;
 	default:
 		BUG_ON(opcode);
 		return -ENOSYS;
@@ -126,7 +134,9 @@ static int acpihp_drv_call_method(enum config_op_code opcode,
 		result = acpihp_drv_invoke_method(opcode, slot, acpi_dev, 0);
 		if (result)
 			break;
-		acpihp_drv_update_dev_state(np, state);
+		if (opcode != DRV_OP_LOCK_DEVICE &&
+		    opcode != DRV_OP_UNLOCK_DEVICE)
+			acpihp_drv_update_dev_state(np, state);
 	}
 	klist_iter_exit(&iter);
 
@@ -248,6 +258,7 @@ int acpihp_drv_configure(struct list_head *list)
 		acpihp_slot_change_state(dep->slot,
 					 ACPIHP_SLOT_STATE_CONFIGURING);
 
+	acpihp_drv_walk_devs(&head, DRV_OP_LOCK_DEVICE, 0, false);
 	result = acpihp_drv_walk_devs(&head, DRV_OP_PRE_CONFIGURE,
 				      DEVICE_STATE_PRE_CONFIGURE, false);
 	if (!result)
@@ -257,6 +268,7 @@ int acpihp_drv_configure(struct list_head *list)
 		post = ACPIHP_DEV_POST_CMD_ROLLBACK;
 	acpihp_drv_walk_devs_post(&head, DRV_OP_POST_CONFIGURE,
 				  DEVICE_STATE_CONNECTED, post, false);
+	acpihp_drv_walk_devs(&head, DRV_OP_UNLOCK_DEVICE, 0, false);
 
 	list_for_each_entry(dep, &head, node)
 		acpihp_drv_update_slot_state(dep->slot);
@@ -327,9 +339,11 @@ int acpihp_drv_unconfigure(struct list_head *list)
 		acpihp_slot_change_state(dep->slot,
 					 ACPIHP_SLOT_STATE_UNCONFIGURING);
 
+	acpihp_drv_walk_devs(&head, DRV_OP_LOCK_DEVICE, 0, false);
 	result = acpihp_drv_release(&head);
 	if (!result)
 		__acpihp_drv_unconfigure(&head);
+	acpihp_drv_walk_devs(&head, DRV_OP_UNLOCK_DEVICE, 0, false);
 
 	list_for_each_entry(dep, &head, node)
 		acpihp_drv_update_slot_state(dep->slot);
diff --git a/drivers/acpi/hotplug/device.c b/drivers/acpi/hotplug/device.c
index d566522..90666f8 100644
--- a/drivers/acpi/hotplug/device.c
+++ b/drivers/acpi/hotplug/device.c
@@ -35,7 +35,6 @@ int acpihp_dev_get_info(struct acpi_device *device,
 
 	acpihp_dev_get_type(device->handle, &info->type);
 
-	device_lock(&device->dev);
 	if (device->driver && device->driver->ops.hp_ops &&
 	    device->driver->ops.hp_ops->get_info)
 		ret = device->driver->ops.hp_ops->get_info(device, info);
@@ -51,7 +50,6 @@ int acpihp_dev_get_info(struct acpi_device *device,
 
 	if (device->driver)
 		info->status |= ACPIHP_DEV_STATUS_ATTACHED;
-	device_unlock(&device->dev);
 
 	return ret;
 }
@@ -62,14 +60,12 @@ int acpihp_dev_##method(struct acpi_device *device, type val) \
 { \
 	int ret; \
 	BUG_ON(device == NULL); \
-	device_lock(&device->dev); \
 	if (!device->driver || !device->driver->ops.hp_ops) \
 		ret = (err); \
 	else if (!device->driver->ops.hp_ops->method) \
 		ret = (def); \
 	else \
 		ret = device->driver->ops.hp_ops->method(device, val); \
-	device_unlock(&device->dev); \
 	return ret; \
 } \
 EXPORT_SYMBOL_GPL(acpihp_dev_##method)
@@ -79,14 +75,12 @@ int acpihp_dev_##method(struct acpi_device *device, type val) \
 { \
 	int ret = 0; \
 	BUG_ON(device == NULL); \
-	device_lock(&device->dev); \
 	if (!device->driver || !device->driver->ops.hp_ops) \
 		ret = (err); \
 	else if (!device->driver->ops.hp_ops->method) \
 		ret = (def); \
 	else \
 		device->driver->ops.hp_ops->method(device, val); \
-	device_unlock(&device->dev); \
 	return ret; \
 } \
 EXPORT_SYMBOL_GPL(acpihp_dev_##method)
@@ -96,14 +90,12 @@ int acpihp_dev_##method(struct acpi_device *device) \
 { \
 	int ret = 0; \
 	BUG_ON(device == NULL); \
-	device_lock(&device->dev); \
 	if (!device->driver || !device->driver->ops.hp_ops) \
 		ret = (err); \
 	else if (!device->driver->ops.hp_ops->method) \
 		ret = (def); \
 	else \
 		device->driver->ops.hp_ops->method(device);\
-	device_unlock(&device->dev); \
 	return ret; \
 } \
 EXPORT_SYMBOL_GPL(acpihp_dev_##method)
-- 
1.7.9.5