s390/scm: Make struct scm_driver::remove return void

The driver core ignores the return value of scmdev_remove()
(because there is only little it can do when a device disappears).

So make it impossible for future drivers to return an unused error code
by changing the remove prototype to return void.

The real motivation for this change is the quest to make struct
bus_type::remove return void, too.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210713193522.1770306-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/s390/include/asm/eadm.h

@@ -105,7 +105,7 @@ enum scm_event {SCM_CHANGE, SCM_AVAIL};
 struct scm_driver {
 	struct device_driver drv;
 	int (*probe) (struct scm_device *scmdev);
-	int (*remove) (struct scm_device *scmdev);
+	void (*remove) (struct scm_device *scmdev);
 	void (*notify) (struct scm_device *scmdev, enum scm_event event);
 	void (*handler) (struct scm_device *scmdev, void *data,
 			blk_status_t error);

drivers/s390/block/scm_drv.c

@@ -60,15 +60,13 @@ static int scm_probe(struct scm_device *scmdev)
 	return ret;
 }
 
-static int scm_remove(struct scm_device *scmdev)
+static void scm_remove(struct scm_device *scmdev)
 {
 	struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
 
 	scm_blk_dev_cleanup(bdev);
 	dev_set_drvdata(&scmdev->dev, NULL);
 	kfree(bdev);
-
-	return 0;
 }
 
 static struct scm_driver scm_drv = {

drivers/s390/cio/scm.c

@@ -33,7 +33,10 @@ static int scmdev_remove(struct device *dev)
 	struct scm_device *scmdev = to_scm_dev(dev);
 	struct scm_driver *scmdrv = to_scm_drv(dev->driver);
 
-	return scmdrv->remove ? scmdrv->remove(scmdev) : -ENODEV;
+	if (scmdrv->remove)
+		scmdrv->remove(scmdev);
+
+	return 0;
 }
 
 static int scmdev_uevent(struct device *dev, struct kobj_uevent_env *env)