1 files changed, 38 insertions, 26 deletions

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 227800053309..0ee96e6fc426 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -446,18 +446,33 @@ static void unregister_dev_dax(void *dev)
 	put_device(dev);
 }
 
+static void dax_region_free(struct kref *kref)
+{
+	struct dax_region *dax_region;
+
+	dax_region = container_of(kref, struct dax_region, kref);
+	kfree(dax_region);
+}
+
+static void dax_region_put(struct dax_region *dax_region)
+{
+	kref_put(&dax_region->kref, dax_region_free);
+}
+
 /* a return value >= 0 indicates this invocation invalidated the id */
 static int __free_dev_dax_id(struct dev_dax *dev_dax)
 {
-	struct dax_region *dax_region = dev_dax->region;
 	struct device *dev = &dev_dax->dev;
+	struct dax_region *dax_region;
 	int rc = dev_dax->id;
 
 	device_lock_assert(dev);
 
-	if (is_static(dax_region) || dev_dax->id < 0)
+	if (!dev_dax->dyn_id || dev_dax->id < 0)
 		return -1;
+	dax_region = dev_dax->region;
 	ida_free(&dax_region->ida, dev_dax->id);
+	dax_region_put(dax_region);
 	dev_dax->id = -1;
 	return rc;
 }
@@ -473,6 +488,20 @@ static int free_dev_dax_id(struct dev_dax *dev_dax)
 	return rc;
 }
 
+static int alloc_dev_dax_id(struct dev_dax *dev_dax)
+{
+	struct dax_region *dax_region = dev_dax->region;
+	int id;
+
+	id = ida_alloc(&dax_region->ida, GFP_KERNEL);
+	if (id < 0)
+		return id;
+	kref_get(&dax_region->kref);
+	dev_dax->dyn_id = true;
+	dev_dax->id = id;
+	return id;
+}
+
 static ssize_t delete_store(struct device *dev, struct device_attribute *attr,
 		const char *buf, size_t len)
 {
@@ -560,20 +589,6 @@ static const struct attribute_group *dax_region_attribute_groups[] = {
 	NULL,
 };
 
-static void dax_region_free(struct kref *kref)
-{
-	struct dax_region *dax_region;
-
-	dax_region = container_of(kref, struct dax_region, kref);
-	kfree(dax_region);
-}
-
-void dax_region_put(struct dax_region *dax_region)
-{
-	kref_put(&dax_region->kref, dax_region_free);
-}
-EXPORT_SYMBOL_GPL(dax_region_put);
-
 static void dax_region_unregister(void *region)
 {
 	struct dax_region *dax_region = region;
@@ -625,7 +640,6 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 		return NULL;
 	}
 
-	kref_get(&dax_region->kref);
 	if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
 		return NULL;
 	return dax_region;
@@ -635,10 +649,12 @@ EXPORT_SYMBOL_GPL(alloc_dax_region);
 static void dax_mapping_release(struct device *dev)
 {
 	struct dax_mapping *mapping = to_dax_mapping(dev);
-	struct dev_dax *dev_dax = to_dev_dax(dev->parent);
+	struct device *parent = dev->parent;
+	struct dev_dax *dev_dax = to_dev_dax(parent);
 
 	ida_free(&dev_dax->ida, mapping->id);
 	kfree(mapping);
+	put_device(parent);
 }
 
 static void unregister_dax_mapping(void *data)
@@ -655,8 +671,7 @@ static void unregister_dax_mapping(void *data)
 	dev_dax->ranges[mapping->range_id].mapping = NULL;
 	mapping->range_id = -1;
 
-	device_del(dev);
-	put_device(dev);
+	device_unregister(dev);
 }
 
 static struct dev_dax_range *get_dax_range(struct device *dev)
@@ -778,6 +793,7 @@ static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id)
 	dev = &mapping->dev;
 	device_initialize(dev);
 	dev->parent = &dev_dax->dev;
+	get_device(dev->parent);
 	dev->type = &dax_mapping_type;
 	dev_set_name(dev, "mapping%d", mapping->id);
 	rc = device_add(dev);
@@ -1295,12 +1311,10 @@ static const struct attribute_group *dax_attribute_groups[] = {
 static void dev_dax_release(struct device *dev)
 {
 	struct dev_dax *dev_dax = to_dev_dax(dev);
-	struct dax_region *dax_region = dev_dax->region;
 	struct dax_device *dax_dev = dev_dax->dax_dev;
 
 	put_dax(dax_dev);
 	free_dev_dax_id(dev_dax);
-	dax_region_put(dax_region);
 	kfree(dev_dax->pgmap);
 	kfree(dev_dax);
 }
@@ -1324,6 +1338,7 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
 	if (!dev_dax)
 		return ERR_PTR(-ENOMEM);
 
+	dev_dax->region = dax_region;
 	if (is_static(dax_region)) {
 		if (dev_WARN_ONCE(parent, data->id < 0,
 				"dynamic id specified to static region\n")) {
@@ -1339,13 +1354,11 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
 			goto err_id;
 		}
 
-		rc = ida_alloc(&dax_region->ida, GFP_KERNEL);
+		rc = alloc_dev_dax_id(dev_dax);
 		if (rc < 0)
 			goto err_id;
-		dev_dax->id = rc;
 	}
 
-	dev_dax->region = dax_region;
 	dev = &dev_dax->dev;
 	device_initialize(dev);
 	dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id);
@@ -1386,7 +1399,6 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
 	dev_dax->target_node = dax_region->target_node;
 	dev_dax->align = dax_region->align;
 	ida_init(&dev_dax->ida);
-	kref_get(&dax_region->kref);
 
 	inode = dax_inode(dax_dev);
 	dev->devt = inode->i_rdev;