Re: [PATCH] vio: make remove callback return void

[Tyrel Datwyler <tyreld@linux.ibm.com>]

On 1/27/21 1:50 PM, Uwe Kleine-König wrote:
> 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 and makes it
> obvious for future driver authors that returning an error code isn't
> intended.
> 
> 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. I didn't care to check which
> driver is using which of these busses (or if even some of them can be
> used with both) and simply adapt all drivers and the two bus codes in
> one go.
> 
> Note that for the powerpc implementation there is a semantical change:
> 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>

> ---
> Hello,
> 
> note that this change depends on
> https://lore.kernel.org/r/20210121062005.53271-1-ljp@linux.ibm.com which removes
> an (ignored) return -EBUSY in drivers/net/ethernet/ibm/ibmvnic.c.
> I don't know when/if this latter patch will be applied, so it might take
> some time until my patch can go in.
> 
> Best regards
> Uwe
> 
>  arch/powerpc/include/asm/vio.h           | 2 +-
>  arch/powerpc/platforms/pseries/vio.c     | 7 +++----
>  arch/sparc/include/asm/vio.h             | 2 +-
>  arch/sparc/kernel/ds.c                   | 6 ------
>  arch/sparc/kernel/vio.c                  | 4 ++--
>  drivers/block/sunvdc.c                   | 3 +--
>  drivers/char/hw_random/pseries-rng.c     | 3 +--
>  drivers/char/tpm/tpm_ibmvtpm.c           | 4 +---
>  drivers/crypto/nx/nx-842-pseries.c       | 4 +---
>  drivers/crypto/nx/nx.c                   | 4 +---
>  drivers/misc/ibmvmc.c                    | 4 +---
>  drivers/net/ethernet/ibm/ibmveth.c       | 4 +---
>  drivers/net/ethernet/ibm/ibmvnic.c       | 4 +---
>  drivers/net/ethernet/sun/ldmvsw.c        | 4 +---
>  drivers/net/ethernet/sun/sunvnet.c       | 3 +--
>  drivers/scsi/ibmvscsi/ibmvfc.c           | 3 +--
>  drivers/scsi/ibmvscsi/ibmvscsi.c         | 4 +---
>  drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 4 +---
>  drivers/tty/hvc/hvcs.c                   | 3 +--
>  drivers/tty/vcc.c                        | 4 +---
>  20 files changed, 22 insertions(+), 54 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/vio.h b/arch/powerpc/include/asm/vio.h
> index 0cf52746531b..721c0d6715ac 100644
> --- a/arch/powerpc/include/asm/vio.h
> +++ b/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.
>  	 */
> diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
> index b2797cfe4e2b..9cb4fc839fd5 100644
> --- a/arch/powerpc/platforms/pseries/vio.c
> +++ b/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;
>  }
>  
>  /**
> diff --git a/arch/sparc/include/asm/vio.h b/arch/sparc/include/asm/vio.h
> index 059f0eb678e0..8a1a83bbb6d5 100644
> --- a/arch/sparc/include/asm/vio.h
> +++ b/arch/sparc/include/asm/vio.h
> @@ -362,7 +362,7 @@ struct vio_driver {
>  	struct list_head		node;
>  	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);
>  	void (*shutdown)(struct vio_dev *dev);
>  	unsigned long			driver_data;
>  	struct device_driver		driver;
> diff --git a/arch/sparc/kernel/ds.c b/arch/sparc/kernel/ds.c
> index 522e5b51050c..4a5bdb0df779 100644
> --- a/arch/sparc/kernel/ds.c
> +++ b/arch/sparc/kernel/ds.c
> @@ -1236,11 +1236,6 @@ static int ds_probe(struct vio_dev *vdev, const struct vio_device_id *id)
>  	return err;
>  }
>  
> -static int ds_remove(struct vio_dev *vdev)
> -{
> -	return 0;
> -}
> -
>  static const struct vio_device_id ds_match[] = {
>  	{
>  		.type = "domain-services-port",
> @@ -1251,7 +1246,6 @@ static const struct vio_device_id ds_match[] = {
>  static struct vio_driver ds_driver = {
>  	.id_table	= ds_match,
>  	.probe		= ds_probe,
> -	.remove		= ds_remove,
>  	.name		= "ds",
>  };
>  
> diff --git a/arch/sparc/kernel/vio.c b/arch/sparc/kernel/vio.c
> index 4f57056ed463..348a88691219 100644
> --- a/arch/sparc/kernel/vio.c
> +++ b/arch/sparc/kernel/vio.c
> @@ -105,10 +105,10 @@ static int vio_device_remove(struct device *dev)
>  		 * routines to do so at the moment. TBD
>  		 */
>  
> -		return drv->remove(vdev);
> +		drv->remove(vdev);
>  	}
>  
> -	return 1;
> +	return 0;
>  }
>  
>  static ssize_t devspec_show(struct device *dev,
> diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
> index 39aeebc6837d..1547d4345ad8 100644
> --- a/drivers/block/sunvdc.c
> +++ b/drivers/block/sunvdc.c
> @@ -1071,7 +1071,7 @@ static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
>  	return err;
>  }
>  
> -static int vdc_port_remove(struct vio_dev *vdev)
> +static void vdc_port_remove(struct vio_dev *vdev)
>  {
>  	struct vdc_port *port = dev_get_drvdata(&vdev->dev);
>  
> @@ -1094,7 +1094,6 @@ static int vdc_port_remove(struct vio_dev *vdev)
>  
>  		kfree(port);
>  	}
> -	return 0;
>  }
>  
>  static void vdc_requeue_inflight(struct vdc_port *port)
> diff --git a/drivers/char/hw_random/pseries-rng.c b/drivers/char/hw_random/pseries-rng.c
> index 8038a8a9fb58..f4949b689bd5 100644
> --- a/drivers/char/hw_random/pseries-rng.c
> +++ b/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[] = {
> diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
> index 994385bf37c0..903604769de9 100644
> --- a/drivers/char/tpm/tpm_ibmvtpm.c
> +++ b/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;
>  }
>  
>  /**
> diff --git a/drivers/crypto/nx/nx-842-pseries.c b/drivers/crypto/nx/nx-842-pseries.c
> index 2de5e3672e42..cc8dd3072b8b 100644
> --- a/drivers/crypto/nx/nx-842-pseries.c
> +++ b/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[] = {
> diff --git a/drivers/crypto/nx/nx.c b/drivers/crypto/nx/nx.c
> index 0d2dc5be7f19..1d0e8a1ba160 100644
> --- a/drivers/crypto/nx/nx.c
> +++ b/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;
>  }
>  
>  
> diff --git a/drivers/misc/ibmvmc.c b/drivers/misc/ibmvmc.c
> index 2d778d0f011e..c0fe3295c330 100644
> --- a/drivers/misc/ibmvmc.c
> +++ b/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[] = {
> diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
> index c3ec9ceed833..7fea9ae60f13 100644
> --- a/drivers/net/ethernet/ibm/ibmveth.c
> +++ b/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;
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
> index a187d51bcf92..2eec0652760c 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.c
> +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> @@ -5430,7 +5430,7 @@ 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);
> @@ -5460,8 +5460,6 @@ 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,
> diff --git a/drivers/net/ethernet/sun/ldmvsw.c b/drivers/net/ethernet/sun/ldmvsw.c
> index 01ea0d6f8819..50bd4e3b0af9 100644
> --- a/drivers/net/ethernet/sun/ldmvsw.c
> +++ b/drivers/net/ethernet/sun/ldmvsw.c
> @@ -404,7 +404,7 @@ static int vsw_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
>  	return err;
>  }
>  
> -static int vsw_port_remove(struct vio_dev *vdev)
> +static void vsw_port_remove(struct vio_dev *vdev)
>  {
>  	struct vnet_port *port = dev_get_drvdata(&vdev->dev);
>  	unsigned long flags;
> @@ -430,8 +430,6 @@ static int vsw_port_remove(struct vio_dev *vdev)
>  
>  		free_netdev(port->dev);
>  	}
> -
> -	return 0;
>  }
>  
>  static void vsw_cleanup(void)
> diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
> index 96b883f965f6..58ee89223951 100644
> --- a/drivers/net/ethernet/sun/sunvnet.c
> +++ b/drivers/net/ethernet/sun/sunvnet.c
> @@ -510,7 +510,7 @@ static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
>  	return err;
>  }
>  
> -static int vnet_port_remove(struct vio_dev *vdev)
> +static void vnet_port_remove(struct vio_dev *vdev)
>  {
>  	struct vnet_port *port = dev_get_drvdata(&vdev->dev);
>  
> @@ -533,7 +533,6 @@ static int vnet_port_remove(struct vio_dev *vdev)
>  
>  		kfree(port);
>  	}
> -	return 0;
>  }
>  
>  static const struct vio_device_id vnet_port_match[] = {
> diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
> index 42e4d35e0d35..0a472acaca5d 100644
> --- a/drivers/scsi/ibmvscsi/ibmvfc.c
> +++ b/drivers/scsi/ibmvscsi/ibmvfc.c
> @@ -5253,7 +5253,7 @@ 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);
>  	unsigned long flags;
> @@ -5282,7 +5282,6 @@ static int ibmvfc_remove(struct vio_dev *vdev)
>  	spin_unlock(&ibmvfc_driver_lock);
>  	scsi_host_put(vhost->host);
>  	LEAVE;
> -	return 0;
>  }
>  
>  /**
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 29fcc44be2d5..77fafb1bc173 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/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;
>  }
>  
>  /**
> diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> index cc3908c2d2f9..9abd9e253af6 100644
> --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> +++ b/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,
> diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c
> index 3e0461285c34..80874945ded8 100644
> --- a/drivers/tty/hvc/hvcs.c
> +++ b/drivers/tty/hvc/hvcs.c
> @@ -819,7 +819,7 @@ 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 +849,6 @@ 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 = {
> diff --git a/drivers/tty/vcc.c b/drivers/tty/vcc.c
> index e2d6205f83ce..5f72ebf93821 100644
> --- a/drivers/tty/vcc.c
> +++ b/drivers/tty/vcc.c
> @@ -677,7 +677,7 @@ static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
>   *
>   * Return: status of removal
>   */
> -static int vcc_remove(struct vio_dev *vdev)
> +static void vcc_remove(struct vio_dev *vdev)
>  {
>  	struct vcc_port *port = dev_get_drvdata(&vdev->dev);
>  
> @@ -712,8 +712,6 @@ static int vcc_remove(struct vio_dev *vdev)
>  		kfree(port->domain);
>  		kfree(port);
>  	}
> -
> -	return 0;
>  }
>  
>  static const struct vio_device_id vcc_match[] = {
>