Re: [PATCH] lib/librte_ether: new filter APIs definition

[Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>]

2014-10-17 07:29, Jingjing Wu:
> Define new APIs to support configure multi-kind filters using same APIs,
> instead of creating each API set for each kind of filter.
>  - rte_eth_dev_filter_supported
>  - rte_eth_dev_filter_ctrl
> 
> Filter types, operations, and structures are defined specifically
> in new header file lib/librte_eth/rte_dev_ctrl.h.
> 
> As to the implementation discussion, please refer to
> http://dpdk.org/ml/archives/dev/2014-September/005179.html
[...]
> --- /dev/null
> +++ b/lib/librte_ether/rte_eth_ctrl.h

Why this name? I think we can reserve this file for filtering API.
So rte_eth_rx_filter.h would be more appropriate.

> +/**
> + * All generic operations to filters
> + */

rewording: "Generic operations on filters"
Could you elaborate on "generic"? What would mean "specific"?

> +enum rte_filter_op {
> +	RTE_ETH_FILTER_OP_NONE = 0,
> +	/**< used to check whether the type filter is supported */
> +	RTE_ETH_FILTER_OP_ADD,      /**< add filter entry */
> +	RTE_ETH_FILTER_OP_UPDATE,   /**< update filter entry */
> +	RTE_ETH_FILTER_OP_DELETE,   /**< delete filter entry */
> +	RTE_ETH_FILTER_OP_FLUSH,    /**< flush all entries */
> +	RTE_ETH_FILTER_OP_GET,      /**< get filter entry */
> +	RTE_ETH_FILTER_OP_SET,      /**< configurations */
> +	RTE_ETH_FILTER_OP_GET_INFO,

Could we remove "OP", except for OP_NONE and OP_MAX?

> +	/**< get information of filter, such as status or statistics */
> +	RTE_ETH_FILTER_OP_MAX,
> +};

> +int
> +rte_eth_dev_filter_supported(uint8_t port_id, enum rte_filter_type filter_type)

This function is really important for compatibility. Good

> +/**
> + * Take operations to assigned filter type on an Ethernet device.
> + * All the supported operations and filter types are defined in 'rte_eth_ctrl.h'.
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param filter_type
> + *   filter type.
> + * @param filter_op
> + *   The operation taken to assigned filter.

Rewording: "Type of operation"

> + * @param arg
> + *   A pointer to arguments defined specifically for the operation.

Actually, arg is specific to the filter type.
Could it be also specific to the operation. Maybe.
I think we will have to explicitly specify which operations can be used with
each structure (in its comments).

> + * @return
> + *   - (0) if successful.
> + *   - (-ENOTSUP) if hardware doesn't support.
> + *   - (-ENODEV) if *port_id* invalid.
> + *   - others depends on the specific operations implementation.
> + */
> +int rte_eth_dev_filter_ctrl(uint8_t port_id, enum rte_filter_type filter_type,
> +			enum rte_filter_op filter_op, void *arg);

Could we add rx in the name? rte_eth_dev_rx_filter_ctrl
If you agree with this naming, it should be added in several other places.

This API is quite simple (which is a good thing).
Let's see how it fits when integrating filtering features.
If something appears to be wrongly designed when integrating a feature
or when implementing it in a driver, feel free to fix the API.

Thanks
-- 
Thomas