dax-device: Make remove callback return void

The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct dax_device_driver::remove()
return void, too. All users already unconditionally return 0, this commit
makes it obvious that returning an error code isn't intended.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-6-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dax/bus.c

@@ -178,12 +178,11 @@ 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);
-	int ret = 0;
 
 	if (dax_drv->remove)
-		ret = dax_drv->remove(dev_dax);
+		dax_drv->remove(dev_dax);
 
-	return ret;
+	return 0;
 }
 
 static struct bus_type dax_bus_type = {

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,

drivers/dax/kmem.c

@@ -136,7 +136,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 }
 
 #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 */