Re: [dpdk-dev] [PATCH v4 1/2] librte_ether: add internal callback functions

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2016-10-04 15:52, Bernard Iremonger:
> add _rte_eth_dev_callback_process_vf function.
> add _rte_eth_dev_callback_process_generic function
> 
> Adding a callback to the user application on VF to PF mailbox message,
> allows passing information to the application controlling the PF
> when a VF mailbox event message is received, such as VF reset.

I have some difficulties to parse this explanation.
Please could you reword it and precise the direction of the message
and the use case context?

> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -2510,6 +2510,20 @@ void
>  _rte_eth_dev_callback_process(struct rte_eth_dev *dev,
>  	enum rte_eth_event_type event)
>  {
> +	return _rte_eth_dev_callback_process_generic(dev, event, NULL);
> +}
> +
> +void
> +_rte_eth_dev_callback_process_vf(struct rte_eth_dev *dev,
> +	enum rte_eth_event_type event, void *param)
> +{
> +	return _rte_eth_dev_callback_process_generic(dev, event, param);
> +}

This function is just adding a parameter, compared to the legacy
_rte_eth_dev_callback_process.
Why calling it process_vf?
And by the way, why not just replacing the legacy function?
As it is a driver interface, there is no ABI restriction.

> +
> +void
> +_rte_eth_dev_callback_process_generic(struct rte_eth_dev *dev,
> +	enum rte_eth_event_type event, void *param)
> +{
[...]
> --- a/lib/librte_ether/rte_ethdev.h
> +++ b/lib/librte_ether/rte_ethdev.h
> @@ -3026,6 +3026,7 @@ enum rte_eth_event_type {
>  				/**< queue state event (enabled/disabled) */
>  	RTE_ETH_EVENT_INTR_RESET,
>  			/**< reset interrupt event, sent to VF on PF reset */
> +	RTE_ETH_EVENT_VF_MBOX,  /**< PF mailbox processing callback */
>  	RTE_ETH_EVENT_MAX       /**< max value of this enum */
>  };

Either we choose to have a "generic" VF event well documented,
or it is just a specific event with a tip on where to find the doc.
Here we need at least to know how to handle the argument.

> +/**
> + * @internal Executes all the user application registered callbacks. Used by:
> + * _rte_eth_dev_callback_process and _rte_eth_dev_callback_process_vf
> + * It is for DPDK internal user only. User application should not call it
> + * directly.
> + *
> + * @param dev
> + *  Pointer to struct rte_eth_dev.
> + * @param event
> + *  Eth device interrupt event type.
> + *
> + * @param param
> + *  parameters to pass back to user application.
> + *
> + * @return
> + *  void
> + */
> +void
> +_rte_eth_dev_callback_process_generic(struct rte_eth_dev *dev,
> +				enum rte_eth_event_type event, void *param);

This is really an internal function and should not be exported at all.