Re: [PATCH v6 4/7] nfc: pn533: Split pn533 init & nfc_register

[Claudiu.Beznea]

On 20.08.2019 15:03, Lars Poeschel wrote:
> There is a problem in the initialisation and setup of the pn533: It
> registers with nfc too early. It could happen, that it finished
> registering with nfc and someone starts using it. But setup of the pn533
> is not yet finished. Bad or at least unintended things could happen.
> So I split out nfc registering (and unregistering) to seperate functions
> that have to be called late in probe then.
> 
> Cc: Johan Hovold <johan@xxxxxxxxxx>
> Signed-off-by: Lars Poeschel <poeschel@xxxxxxxxxxx>
> ---
> Changes in v6:
> - Rebased the patch series on v5.3-rc5
> 
> Changes in v5:
> - This patch is new in v5
> 
>  drivers/nfc/pn533/i2c.c   | 17 +++++-----
>  drivers/nfc/pn533/pn533.c | 66 ++++++++++++++++++++-------------------
>  drivers/nfc/pn533/pn533.h | 11 ++++---
>  drivers/nfc/pn533/usb.c   | 12 +++++--
>  4 files changed, 59 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/nfc/pn533/i2c.c b/drivers/nfc/pn533/i2c.c
> index 1abd40398a5a..e9e5a1ec8857 100644
> --- a/drivers/nfc/pn533/i2c.c
> +++ b/drivers/nfc/pn533/i2c.c
> @@ -193,12 +193,10 @@ static int pn533_i2c_probe(struct i2c_client *client,
>  	phy->i2c_dev = client;
>  	i2c_set_clientdata(client, phy);
>  
> -	priv = pn533_register_device(PN533_DEVICE_PN532,
> -				     PN533_NO_TYPE_B_PROTOCOLS,
> +	priv = pn53x_common_init(PN533_DEVICE_PN532,
>  				     PN533_PROTO_REQ_ACK_RESP,
>  				     phy, &i2c_phy_ops, NULL,
> -				     &phy->i2c_dev->dev,
> -				     &client->dev);
> +				     &phy->i2c_dev->dev);
>  
>  	if (IS_ERR(priv)) {
>  		r = PTR_ERR(priv);
> @@ -220,13 +218,17 @@ static int pn533_i2c_probe(struct i2c_client *client,
>  	if (r)
>  		goto fn_setup_err;
>  
> -	return 0;
> +	r = pn53x_register_nfc(priv, PN533_NO_TYPE_B_PROTOCOLS, &client->dev);
> +	if (r)
> +		goto fn_setup_err;
> +
> +	return r;
>  
>  fn_setup_err:
>  	free_irq(client->irq, phy);
>  
>  irq_rqst_err:
> -	pn533_unregister_device(phy->priv);
> +	pn53x_common_clean(phy->priv);
>  
>  	return r;
>  }
> @@ -239,7 +241,8 @@ static int pn533_i2c_remove(struct i2c_client *client)
>  
>  	free_irq(client->irq, phy);
>  
> -	pn533_unregister_device(phy->priv);
> +	pn53x_unregister_nfc(phy->priv);
> +	pn53x_common_clean(phy->priv);
>  
>  	return 0;
>  }
> diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c
> index 64836c727aee..a8c756caa678 100644
> --- a/drivers/nfc/pn533/pn533.c
> +++ b/drivers/nfc/pn533/pn533.c
> @@ -2590,14 +2590,12 @@ int pn533_finalize_setup(struct pn533 *dev)
>  }
>  EXPORT_SYMBOL_GPL(pn533_finalize_setup);
>  
> -struct pn533 *pn533_register_device(u32 device_type,
> -				u32 protocols,
> +struct pn533 *pn53x_common_init(u32 device_type,
>  				enum pn533_protocol_type protocol_type,
>  				void *phy,
>  				struct pn533_phy_ops *phy_ops,
>  				struct pn533_frame_ops *fops,
> -				struct device *dev,
> -				struct device *parent)
> +				struct device *dev)
>  {
>  	struct pn533 *priv;
>  	int rc = -ENOMEM;
> @@ -2638,43 +2636,18 @@ struct pn533 *pn533_register_device(u32 device_type,
>  	skb_queue_head_init(&priv->fragment_skb);
>  
>  	INIT_LIST_HEAD(&priv->cmd_queue);
> -
> -	priv->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols,
> -					   priv->ops->tx_header_len +
> -					   PN533_CMD_DATAEXCH_HEAD_LEN,
> -					   priv->ops->tx_tail_len);
> -	if (!priv->nfc_dev) {
> -		rc = -ENOMEM;
> -		goto destroy_wq;
> -	}
> -
> -	nfc_set_parent_dev(priv->nfc_dev, parent);
> -	nfc_set_drvdata(priv->nfc_dev, priv);
> -
> -	rc = nfc_register_device(priv->nfc_dev);
> -	if (rc)
> -		goto free_nfc_dev;
> -
>  	return priv;
>  
> -free_nfc_dev:
> -	nfc_free_device(priv->nfc_dev);
> -
> -destroy_wq:
> -	destroy_workqueue(priv->wq);
>  error:
>  	kfree(priv);
>  	return ERR_PTR(rc);
>  }
> -EXPORT_SYMBOL_GPL(pn533_register_device);
> +EXPORT_SYMBOL_GPL(pn53x_common_init);
>  
> -void pn533_unregister_device(struct pn533 *priv)
> +void pn53x_common_clean(struct pn533 *priv)
>  {
>  	struct pn533_cmd *cmd, *n;
>  
> -	nfc_unregister_device(priv->nfc_dev);
> -	nfc_free_device(priv->nfc_dev);
> -
>  	flush_delayed_work(&priv->poll_work);
>  	destroy_workqueue(priv->wq);
>  
> @@ -2689,8 +2662,37 @@ void pn533_unregister_device(struct pn533 *priv)
>  
>  	kfree(priv);
>  }
> -EXPORT_SYMBOL_GPL(pn533_unregister_device);
> +EXPORT_SYMBOL_GPL(pn53x_common_clean);
> +
> +int pn53x_register_nfc(struct pn533 *priv, u32 protocols,
> +			struct device *parent)
> +{
> +	int rc = -ENOMEM;

No need to initialize rc here... or just return rc below.

> +
> +	priv->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols,
> +					   priv->ops->tx_header_len +
> +					   PN533_CMD_DATAEXCH_HEAD_LEN,
> +					   priv->ops->tx_tail_len);
> +	if (!priv->nfc_dev)
> +		return -ENOMEM;
> +
> +	nfc_set_parent_dev(priv->nfc_dev, parent);
> +	nfc_set_drvdata(priv->nfc_dev, priv);
> +
> +	rc = nfc_register_device(priv->nfc_dev);
> +	if (rc)
> +		nfc_free_device(priv->nfc_dev);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(pn53x_register_nfc);
>  
> +void pn53x_unregister_nfc(struct pn533 *priv)
> +{
> +	nfc_unregister_device(priv->nfc_dev);
> +	nfc_free_device(priv->nfc_dev);
> +}
> +EXPORT_SYMBOL_GPL(pn53x_unregister_nfc);
>  
>  MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@xxxxxxxxxxxxx>");
>  MODULE_AUTHOR("Aloisio Almeida Jr <aloisio.almeida@xxxxxxxxxxxxx>");
> diff --git a/drivers/nfc/pn533/pn533.h b/drivers/nfc/pn533/pn533.h
> index 570ee0a3e832..510ddebbd896 100644
> --- a/drivers/nfc/pn533/pn533.h
> +++ b/drivers/nfc/pn533/pn533.h
> @@ -219,18 +219,19 @@ struct pn533_phy_ops {
>  };
>  
>  
> -struct pn533 *pn533_register_device(u32 device_type,
> -				u32 protocols,
> +struct pn533 *pn53x_common_init(u32 device_type,
>  				enum pn533_protocol_type protocol_type,
>  				void *phy,
>  				struct pn533_phy_ops *phy_ops,
>  				struct pn533_frame_ops *fops,
> -				struct device *dev,
> -				struct device *parent);
> +				struct device *dev);
>  
>  int pn533_finalize_setup(struct pn533 *dev);
> -void pn533_unregister_device(struct pn533 *priv);
> +void pn53x_common_clean(struct pn533 *priv);
>  void pn533_recv_frame(struct pn533 *dev, struct sk_buff *skb, int status);
> +int pn53x_register_nfc(struct pn533 *priv, u32 protocols,
> +			struct device *parent);
> +void pn53x_unregister_nfc(struct pn533 *priv);
>  
>  bool pn533_rx_frame_is_cmd_response(struct pn533 *dev, void *frame);
>  bool pn533_rx_frame_is_ack(void *_frame);
> diff --git a/drivers/nfc/pn533/usb.c b/drivers/nfc/pn533/usb.c
> index c5289eaf17ee..a1c6a41944c6 100644
> --- a/drivers/nfc/pn533/usb.c
> +++ b/drivers/nfc/pn533/usb.c
> @@ -534,9 +534,9 @@ static int pn533_usb_probe(struct usb_interface *interface,
>  		goto error;
>  	}
>  
> -	priv = pn533_register_device(id->driver_info, protocols, protocol_type,
> +	priv = pn53x_common_init(id->driver_info, protocol_type,
>  					phy, &usb_phy_ops, fops,
> -					&phy->udev->dev, &interface->dev);
> +					&phy->udev->dev);
>  
>  	if (IS_ERR(priv)) {
>  		rc = PTR_ERR(priv);
> @@ -550,9 +550,14 @@ static int pn533_usb_probe(struct usb_interface *interface,
>  		goto error;
>  
>  	usb_set_intfdata(interface, phy);

Above this instruction there is this code:

	rc = pn533_finalize_setup(priv);
	if (rc)
		goto error;

Instead of "goto error;" you should have "goto err_clean;"

> +	rc = pn53x_register_nfc(priv, protocols, &interface->dev);
> +	if (rc)
> +		goto err_clean;
>  
>  	return 0;
>  
> +err_clean:
> +	pn53x_common_clean(priv);
>  error:
>  	usb_free_urb(phy->in_urb);
>  	usb_free_urb(phy->out_urb);
> @@ -570,7 +575,8 @@ static void pn533_usb_disconnect(struct usb_interface *interface)
>  	if (!phy)
>  		return;
>  
> -	pn533_unregister_device(phy->priv);
> +	pn53x_unregister_nfc(phy->priv);
> +	pn53x_common_clean(phy->priv);
>  
>  	usb_set_intfdata(interface, NULL);
>  
>