vio: 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 vio_driver::remove() return
void, too. All users already unconditionally return 0, this commit makes
it obvious that returning an error code is a bad idea.

Note there are two nominally different implementations for a vio bus:
one in arch/sparc/kernel/vio.c and the other in
arch/powerpc/platforms/pseries/vio.c. This patch only adapts the powerpc
one.

Before this patch for a device that was bound to a driver without a
remove callback vio_cmo_bus_remove(viodev) wasn't called. As the device
core still considers the device unbound after vio_bus_remove() returns
calling this unconditionally is the consistent behaviour which is
implemented here.
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Acked-by: Lijun Pan <ljp@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[mpe: Drop unneeded hvcs_remove() forward declaration, squash in
 change from sfr to drop ibmvnic_remove() forward declaration]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210225221834.160083-1-uwe@kleine-koenig.org

arch/powerpc/include/asm/vio.h

@@ -113,7 +113,7 @@ struct vio_driver {
 	const char *name;
 	const struct vio_device_id *id_table;
 	int (*probe)(struct vio_dev *dev, const struct vio_device_id *id);
-	int (*remove)(struct vio_dev *dev);
+	void (*remove)(struct vio_dev *dev);
 	/* A driver must have a get_desired_dma() function to
 	 * be loaded in a CMO environment if it uses DMA.
 	 */

arch/powerpc/platforms/pseries/vio.c

@@ -1261,7 +1261,6 @@ static int vio_bus_remove(struct device *dev)
 	struct vio_dev *viodev = to_vio_dev(dev);
 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
 	struct device *devptr;
-	int ret = 1;
 
 	/*
 	 * Hold a reference to the device after the remove function is called
@@ -1270,13 +1269,13 @@ static int vio_bus_remove(struct device *dev)
 	devptr = get_device(dev);
 
 	if (viodrv->remove)
-		ret = viodrv->remove(viodev);
+		viodrv->remove(viodev);
 
-	if (!ret && firmware_has_feature(FW_FEATURE_CMO))
+	if (firmware_has_feature(FW_FEATURE_CMO))
 		vio_cmo_bus_remove(viodev);
 
 	put_device(devptr);
-	return ret;
+	return 0;
 }
 
 /**

drivers/char/hw_random/pseries-rng.c

@@ -54,10 +54,9 @@ static int pseries_rng_probe(struct vio_dev *dev,
 	return hwrng_register(&pseries_rng);
 }
 
-static int pseries_rng_remove(struct vio_dev *dev)
+static void pseries_rng_remove(struct vio_dev *dev)
 {
 	hwrng_unregister(&pseries_rng);
-	return 0;
 }
 
 static const struct vio_device_id pseries_rng_driver_ids[] = {

drivers/char/tpm/tpm_ibmvtpm.c

@@ -343,7 +343,7 @@ static int ibmvtpm_crq_send_init_complete(struct ibmvtpm_dev *ibmvtpm)
  *
  * Return: Always 0.
  */
-static int tpm_ibmvtpm_remove(struct vio_dev *vdev)
+static void tpm_ibmvtpm_remove(struct vio_dev *vdev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(&vdev->dev);
 	struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
@@ -372,8 +372,6 @@ static int tpm_ibmvtpm_remove(struct vio_dev *vdev)
 	kfree(ibmvtpm);
 	/* For tpm_ibmvtpm_get_desired_dma */
 	dev_set_drvdata(&vdev->dev, NULL);
-
-	return 0;
 }
 
 /**

drivers/crypto/nx/nx-842-pseries.c

@@ -1042,7 +1042,7 @@ static int nx842_probe(struct vio_dev *viodev,
 	return ret;
 }
 
-static int nx842_remove(struct vio_dev *viodev)
+static void nx842_remove(struct vio_dev *viodev)
 {
 	struct nx842_devdata *old_devdata;
 	unsigned long flags;
@@ -1063,8 +1063,6 @@ static int nx842_remove(struct vio_dev *viodev)
 	if (old_devdata)
 		kfree(old_devdata->counters);
 	kfree(old_devdata);
-
-	return 0;
 }
 
 static const struct vio_device_id nx842_vio_driver_ids[] = {

drivers/crypto/nx/nx.c

@@ -783,7 +783,7 @@ static int nx_probe(struct vio_dev *viodev, const struct vio_device_id *id)
 	return nx_register_algs();
 }
 
-static int nx_remove(struct vio_dev *viodev)
+static void nx_remove(struct vio_dev *viodev)
 {
 	dev_dbg(&viodev->dev, "entering nx_remove for UA 0x%x\n",
 		viodev->unit_address);
@@ -811,8 +811,6 @@ static int nx_remove(struct vio_dev *viodev)
 		nx_unregister_skcipher(&nx_ecb_aes_alg, NX_FC_AES,
 				       NX_MODE_AES_ECB);
 	}
-
-	return 0;
 }
 
 

drivers/misc/ibmvmc.c

@@ -2288,15 +2288,13 @@ static int ibmvmc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 	return -EPERM;
 }
 
-static int ibmvmc_remove(struct vio_dev *vdev)
+static void ibmvmc_remove(struct vio_dev *vdev)
 {
 	struct crq_server_adapter *adapter = dev_get_drvdata(&vdev->dev);
 
 	dev_info(adapter->dev, "Entering remove for UA 0x%x\n",
 		 vdev->unit_address);
 	ibmvmc_release_crq_queue(adapter);
-
-	return 0;
 }
 
 static struct vio_device_id ibmvmc_device_table[] = {

drivers/net/ethernet/ibm/ibmveth.c

@@ -1758,7 +1758,7 @@ static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	return 0;
 }
 
-static int ibmveth_remove(struct vio_dev *dev)
+static void ibmveth_remove(struct vio_dev *dev)
 {
 	struct net_device *netdev = dev_get_drvdata(&dev->dev);
 	struct ibmveth_adapter *adapter = netdev_priv(netdev);
@@ -1771,8 +1771,6 @@ static int ibmveth_remove(struct vio_dev *dev)
 
 	free_netdev(netdev);
 	dev_set_drvdata(&dev->dev, NULL);
-
-	return 0;
 }
 
 static struct attribute veth_active_attr;

drivers/net/ethernet/ibm/ibmvnic.c

@@ -78,7 +78,6 @@ MODULE_LICENSE("GPL");
 MODULE_VERSION(IBMVNIC_DRIVER_VERSION);
 
 static int ibmvnic_version = IBMVNIC_INITIAL_VERSION;
-static int ibmvnic_remove(struct vio_dev *);
 static void release_sub_crqs(struct ibmvnic_adapter *, bool);
 static int ibmvnic_reset_crq(struct ibmvnic_adapter *);
 static int ibmvnic_send_crq_init(struct ibmvnic_adapter *);
@@ -5396,7 +5395,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	return rc;
 }
 
-static int ibmvnic_remove(struct vio_dev *dev)
+static void ibmvnic_remove(struct vio_dev *dev)
 {
 	struct net_device *netdev = dev_get_drvdata(&dev->dev);
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
@@ -5437,8 +5436,6 @@ static int ibmvnic_remove(struct vio_dev *dev)
 	device_remove_file(&dev->dev, &dev_attr_failover);
 	free_netdev(netdev);
 	dev_set_drvdata(&dev->dev, NULL);
-
-	return 0;
 }
 
 static ssize_t failover_store(struct device *dev, struct device_attribute *attr,

drivers/scsi/ibmvscsi/ibmvfc.c

@@ -6038,7 +6038,7 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
  * Return value:
  * 	0
  **/
-static int ibmvfc_remove(struct vio_dev *vdev)
+static void ibmvfc_remove(struct vio_dev *vdev)
 {
 	struct ibmvfc_host *vhost = dev_get_drvdata(&vdev->dev);
 	LIST_HEAD(purge);
@@ -6070,7 +6070,6 @@ static int ibmvfc_remove(struct vio_dev *vdev)
 	spin_unlock(&ibmvfc_driver_lock);
 	scsi_host_put(vhost->host);
 	LEAVE;
-	return 0;
 }
 
 /**

drivers/scsi/ibmvscsi/ibmvscsi.c

@@ -2335,7 +2335,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 	return -1;
 }
 
-static int ibmvscsi_remove(struct vio_dev *vdev)
+static void ibmvscsi_remove(struct vio_dev *vdev)
 {
 	struct ibmvscsi_host_data *hostdata = dev_get_drvdata(&vdev->dev);
 
@@ -2356,8 +2356,6 @@ static int ibmvscsi_remove(struct vio_dev *vdev)
 	spin_unlock(&ibmvscsi_driver_lock);
 
 	scsi_host_put(hostdata->host);
-
-	return 0;
 }
 
 /**

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c

@@ -3595,7 +3595,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
 	return rc;
 }
 
-static int ibmvscsis_remove(struct vio_dev *vdev)
+static void ibmvscsis_remove(struct vio_dev *vdev)
 {
 	struct scsi_info *vscsi = dev_get_drvdata(&vdev->dev);
 
@@ -3622,8 +3622,6 @@ static int ibmvscsis_remove(struct vio_dev *vdev)
 	list_del(&vscsi->list);
 	spin_unlock_bh(&ibmvscsis_dev_lock);
 	kfree(vscsi);
-
-	return 0;
 }
 
 static ssize_t system_id_show(struct device *dev,

drivers/tty/hvc/hvcs.c

@@ -317,7 +317,6 @@ static void hvcs_hangup(struct tty_struct * tty);
 
 static int hvcs_probe(struct vio_dev *dev,
 		const struct vio_device_id *id);
-static int hvcs_remove(struct vio_dev *dev);
 static int __init hvcs_module_init(void);
 static void __exit hvcs_module_exit(void);
 static int hvcs_initialize(void);
@@ -819,7 +818,7 @@ static int hvcs_probe(
 	return 0;
 }
 
-static int hvcs_remove(struct vio_dev *dev)
+static void hvcs_remove(struct vio_dev *dev)
 {
 	struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);
 	unsigned long flags;
@@ -849,7 +848,6 @@ static int hvcs_remove(struct vio_dev *dev)
 
 	printk(KERN_INFO "HVCS: vty-server@%X removed from the"
 			" vio bus.\n", dev->unit_address);
-	return 0;
 };
 
 static struct vio_driver hvcs_vio_driver = {