1 files changed, 23 insertions, 32 deletions

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index e3a384182fe7..227800053309 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -56,6 +56,25 @@ static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
 	return match;
 }
 
+static int dax_match_type(struct dax_device_driver *dax_drv, struct device *dev)
+{
+	enum dax_driver_type type = DAXDRV_DEVICE_TYPE;
+	struct dev_dax *dev_dax = to_dev_dax(dev);
+
+	if (dev_dax->region->res.flags & IORESOURCE_DAX_KMEM)
+		type = DAXDRV_KMEM_TYPE;
+
+	if (dax_drv->type == type)
+		return 1;
+
+	/* default to device mode if dax_kmem is disabled */
+	if (dax_drv->type == DAXDRV_DEVICE_TYPE &&
+	    !IS_ENABLED(CONFIG_DEV_DAX_KMEM))
+		return 1;
+
+	return 0;
+}
+
 enum id_action {
 	ID_REMOVE,
 	ID_ADD,
@@ -216,14 +235,9 @@ static int dax_bus_match(struct device *dev, struct device_driver *drv)
 {
 	struct dax_device_driver *dax_drv = to_dax_drv(drv);
 
-	/*
-	 * All but the 'device-dax' driver, which has 'match_always'
-	 * set, requires an exact id match.
-	 */
-	if (dax_drv->match_always)
+	if (dax_match_id(dax_drv, dev))
 		return 1;
-
-	return dax_match_id(dax_drv, dev);
+	return dax_match_type(dax_drv, dev);
 }
 
 /*
@@ -427,8 +441,8 @@ static void unregister_dev_dax(void *dev)
 	dev_dbg(dev, "%s\n", __func__);
 
 	kill_dev_dax(dev_dax);
-	free_dev_dax_ranges(dev_dax);
 	device_del(dev);
+	free_dev_dax_ranges(dev_dax);
 	put_device(dev);
 }
 
@@ -1413,13 +1427,10 @@ err_id:
 }
 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
 
-static int match_always_count;
-
 int __dax_driver_register(struct dax_device_driver *dax_drv,
 		struct module *module, const char *mod_name)
 {
 	struct device_driver *drv = &dax_drv->drv;
-	int rc = 0;
 
 	/*
 	 * dax_bus_probe() calls dax_drv->probe() unconditionally.
@@ -1434,26 +1445,7 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
 	drv->mod_name = mod_name;
 	drv->bus = &dax_bus_type;
 
-	/* there can only be one default driver */
-	mutex_lock(&dax_bus_lock);
-	match_always_count += dax_drv->match_always;
-	if (match_always_count > 1) {
-		match_always_count--;
-		WARN_ON(1);
-		rc = -EINVAL;
-	}
-	mutex_unlock(&dax_bus_lock);
-	if (rc)
-		return rc;
-
-	rc = driver_register(drv);
-	if (rc && dax_drv->match_always) {
-		mutex_lock(&dax_bus_lock);
-		match_always_count -= dax_drv->match_always;
-		mutex_unlock(&dax_bus_lock);
-	}
-
-	return rc;
+	return driver_register(drv);
 }
 EXPORT_SYMBOL_GPL(__dax_driver_register);
 
@@ -1463,7 +1455,6 @@ void dax_driver_unregister(struct dax_device_driver *dax_drv)
 	struct dax_id *dax_id, *_id;
 
 	mutex_lock(&dax_bus_lock);
-	match_always_count -= dax_drv->match_always;
 	list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) {
 		list_del(&dax_id->list);
 		kfree(dax_id);