Re: [PATCH v3 2/4] usb: typec: ucsi: add a common function ucsi_unregister_connectors()

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Wed, Apr 13, 2022 at 05:58:09PM +0800, Linyu Yuan wrote:
> In error path of ucsi_init(), it will unregister all valid ucsi connector,
> and samiliar operation also happen in ucsi_unregister(),

Sorry but I have to confirm this: with "samiliar" you mean "the same",
right?

> add a common function for two places.
> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> ---
> v2: improve ucsi_connector_clean(), check total number of connector.
> v3: rename to ucsi_unregister_connectors(), suggest by maintainer
> 
>  drivers/usb/typec/ucsi/ucsi.c | 51 ++++++++++++++++++++++++-------------------
>  1 file changed, 28 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index 77ac0b7..af9a2a1 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1187,6 +1187,32 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
>  	return ret;
>  }
>  
> +static void ucsi_unregister_connectors(struct ucsi *ucsi)
> +{
> +	struct ucsi_connector *con;
> +	int i;
> +
> +	if (!ucsi->connector)
> +		return;

Can that actually ever happen?

> +	for (i = 0; i < ucsi->cap.num_connectors; i++) {
> +		con = &ucsi->connector[i];
> +		if (!con->port)
> +			break;
> +
> +		cancel_work_sync(&con->work);
> +		ucsi_unregister_partner(con);
> +		ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON);
> +		ucsi_unregister_port_psy(con);
> +		if (con->wq)
> +			destroy_workqueue(con->wq);
> +		typec_unregister_port(con->port);
> +	}
> +
> +	kfree(ucsi->connector);
> +	ucsi->connector = NULL;
> +}

Another way of doing this would be to just remove a single connector
in the function, and leave the loops to the callers.

static void ucsi_unregister_connector(struct ucsi_connector *con)
{
        cancel_work_sync(&con->work);
        ucsi_unregister_partner(con);
        ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON);
        ucsi_unregister_port_psy(con);
        if (con->wq)
                destroy_workqueue(con->wq);
        typec_unregister_port(con->port);
}

I wonder would it actually be a bit more clearer to do it like that...
I'll leave the decision to you.

>  /**
>   * ucsi_init - Initialize UCSI interface
>   * @ucsi: UCSI to be initialized
> @@ -1195,7 +1221,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
>   */
>  static int ucsi_init(struct ucsi *ucsi)
>  {
> -	struct ucsi_connector *con;
>  	u64 command;
>  	int ret;
>  	int i;
> @@ -1250,15 +1275,7 @@ static int ucsi_init(struct ucsi *ucsi)
>  	return 0;
>  
>  err_unregister:
> -	for (con = ucsi->connector; con->port; con++) {
> -		ucsi_unregister_partner(con);
> -		ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON);
> -		ucsi_unregister_port_psy(con);
> -		if (con->wq)
> -			destroy_workqueue(con->wq);
> -		typec_unregister_port(con->port);
> -		con->port = NULL;
> -	}
> +	ucsi_unregister_connectors(ucsi);
>  
>  err_reset:
>  	memset(&ucsi->cap, 0, sizeof(ucsi->cap));
> @@ -1364,7 +1381,6 @@ EXPORT_SYMBOL_GPL(ucsi_register);
>  void ucsi_unregister(struct ucsi *ucsi)
>  {
>  	u64 cmd = UCSI_SET_NOTIFICATION_ENABLE;
> -	int i;
>  
>  	/* Make sure that we are not in the middle of driver initialization */
>  	cancel_work_sync(&ucsi->work);
> @@ -1372,18 +1388,7 @@ void ucsi_unregister(struct ucsi *ucsi)
>  	/* Disable notifications */
>  	ucsi->ops->async_write(ucsi, UCSI_CONTROL, &cmd, sizeof(cmd));
>  
> -	for (i = 0; i < ucsi->cap.num_connectors; i++) {
> -		cancel_work_sync(&ucsi->connector[i].work);
> -		ucsi_unregister_partner(&ucsi->connector[i]);
> -		ucsi_unregister_altmodes(&ucsi->connector[i],
> -					 UCSI_RECIPIENT_CON);
> -		ucsi_unregister_port_psy(&ucsi->connector[i]);
> -		if (ucsi->connector[i].wq)
> -			destroy_workqueue(ucsi->connector[i].wq);
> -		typec_unregister_port(ucsi->connector[i].port);
> -	}
> -
> -	kfree(ucsi->connector);
> +	ucsi_unregister_connectors(ucsi);
>  }
>  EXPORT_SYMBOL_GPL(ucsi_unregister);

thanks,

-- 
heikki