From patchwork series 498731

https://patchwork.ozlabs.org//project/linuxppc-dev/list/?series=498731

Author: Fox Snowpatch

drivers/hv/vmbus_drv.c

@@ -541,34 +541,6 @@ static ssize_t device_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(device);
 
-static ssize_t driver_override_store(struct device *dev,
-				     struct device_attribute *attr,
-				     const char *buf, size_t count)
-{
-	struct hv_device *hv_dev = device_to_hv_device(dev);
-	int ret;
-
-	ret = driver_set_override(dev, &hv_dev->driver_override, buf, count);
-	if (ret)
-		return ret;
-
-	return count;
-}
-
-static ssize_t driver_override_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct hv_device *hv_dev = device_to_hv_device(dev);
-	ssize_t len;
-
-	device_lock(dev);
-	len = sysfs_emit(buf, "%s\n", hv_dev->driver_override);
-	device_unlock(dev);
-
-	return len;
-}
-static DEVICE_ATTR_RW(driver_override);
-
 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_id.attr,
@@ -599,7 +571,6 @@ static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_channel_vp_mapping.attr,
 	&dev_attr_vendor.attr,
 	&dev_attr_device.attr,
-	&dev_attr_driver_override.attr,
 	NULL,
 };
 
@@ -711,18 +682,23 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver *
 {
 	const guid_t *guid = &dev->dev_type;
 	const struct hv_vmbus_device_id *id;
+	int ret;
 
-	/* When driver_override is set, only bind to the matching driver */
-	if (dev->driver_override && strcmp(dev->driver_override, drv->name))
+	/* If a driver override is set, only bind to the matching driver */
+	ret = device_match_driver_override(&dev->device, &drv->driver);
+	if (ret == 0)
 		return NULL;
 
 	/* Look at the dynamic ids first, before the static ones */
 	id = hv_vmbus_dynid_match((struct hv_driver *)drv, guid);
 	if (!id)
 		id = hv_vmbus_dev_match(drv->id_table, guid);
 
-	/* driver_override will always match, send a dummy id */
-	if (!id && dev->driver_override)
+	/*
+	 * If there's a matching driver override, this function should succeed,
+	 * thus return a dummy device ID if no matching ID is found.
+	 */
+	if (!id && ret > 0)
 		id = &vmbus_device_null;
 
 	return id;
@@ -1024,6 +1000,7 @@ static const struct dev_pm_ops vmbus_pm = {
 /* The one and only one */
 static const struct bus_type  hv_bus = {
 	.name =		"vmbus",
+	.driver_override =	true,
 	.match =		vmbus_match,
 	.shutdown =		vmbus_shutdown,
 	.remove =		vmbus_remove,

include/linux/hyperv.h

@@ -1272,11 +1272,6 @@ struct hv_device {
 	u16 device_id;
 
 	struct device device;
-	/*
-	 * Driver name to force a match.  Do not set directly, because core
-	 * frees it.  Use driver_set_override() to set or clear it.
-	 */
-	const char *driver_override;
 
 	struct vmbus_channel *channel;
 	struct kset	     *channels_kset;