4 files changed, 25 insertions, 16 deletions
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 737b207c9e30..452e85ae87a8 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -179,7 +179,10 @@ static int dax_bus_remove(struct device *dev)
 	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
 	struct dev_dax *dev_dax = to_dev_dax(dev);
 
-	return dax_drv->remove(dev_dax);
+	if (dax_drv->remove)
+		dax_drv->remove(dev_dax);
+
+	return 0;
 }
 
 static struct bus_type dax_bus_type = {
@@ -1038,7 +1041,7 @@ static ssize_t range_parse(const char *opt, size_t len, struct range *range)
 {
 	unsigned long long addr = 0;
 	char *start, *end, *str;
-	ssize_t rc = EINVAL;
+	ssize_t rc = -EINVAL;
 
 	str = kstrdup(opt, GFP_KERNEL);
 	if (!str)
@@ -1392,6 +1395,13 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
 	struct device_driver *drv = &dax_drv->drv;
 	int rc = 0;
 
+	/*
+	 * dax_bus_probe() calls dax_drv->probe() unconditionally.
+	 * So better be safe than sorry and ensure it is provided.
+	 */
+	if (!dax_drv->probe)
+		return -EINVAL;
+
 	INIT_LIST_HEAD(&dax_drv->ids);
 	drv->owner = module;
 	drv->name = mod_name;
@@ -1409,7 +1419,15 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
 	mutex_unlock(&dax_bus_lock);
 	if (rc)
 		return rc;
-	return driver_register(drv);
+
+	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;
 }
 EXPORT_SYMBOL_GPL(__dax_driver_register);
 
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 72b92f95509f..1e946ad7780a 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -39,7 +39,7 @@ struct dax_device_driver {
 	struct list_head ids;
 	int match_always;
 	int (*probe)(struct dev_dax *dev);
-	int (*remove)(struct dev_dax *dev);
+	void (*remove)(struct dev_dax *dev);
 };
 
 int __dax_driver_register(struct dax_device_driver *dax_drv,
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 5da2980bb16b..db92573c94e8 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -452,15 +452,9 @@ int dev_dax_probe(struct dev_dax *dev_dax)
 }
 EXPORT_SYMBOL_GPL(dev_dax_probe);
 
-static int dev_dax_remove(struct dev_dax *dev_dax)
-{
-	/* all probe actions are unwound by devm */
-	return 0;
-}
-
 static struct dax_device_driver device_dax_driver = {
 	.probe = dev_dax_probe,
-	.remove = dev_dax_remove,
+	/* all probe actions are unwound by devm, so .remove isn't necessary */
 	.match_always = 1,
 };
 
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 403ec42472d1..ac231cc36359 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -136,7 +136,7 @@ err_res_name:
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
+static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
 	int i, success = 0;
 	struct device *dev = &dev_dax->dev;
@@ -176,11 +176,9 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
 		kfree(data);
 		dev_set_drvdata(dev, NULL);
 	}
-
-	return 0;
 }
 #else
-static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
+static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
 	/*
 	 * Without hotremove purposely leak the request_mem_region() for the
@@ -190,7 +188,6 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
 	 * request_mem_region().
 	 */
 	any_hotremove_failed = true;
-	return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */