[dpdk-dev] Questions about API with no parameter check

Ferruh Yigit ferruh.yigit at intel.com
Wed Apr 7 18:10:00 CEST 2021


On 4/7/2021 4:25 PM, Hemant Agrawal wrote:
> 
> On 4/7/2021 8:10 PM, Ajit Khaparde wrote:
>> On Wed, Apr 7, 2021 at 6:20 AM Jerin Jacob <jerinjacobk at gmail.com> wrote:
>>> On Wed, Apr 7, 2021 at 5:23 PM Ananyev, Konstantin
>>> <konstantin.ananyev at intel.com> wrote:
>>>>
>>>>
>>>>> 07/04/2021 13:28, Min Hu (Connor):
>>>>>> Hi, all,
>>>>>>      Many APIs in DPDK does not check if the pointer parameter is
>>>>>> NULL or not. For example, in 'rte_ethdev.c':
>>>>>> int
>>>>>> rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
>>>>>>                     uint16_t nb_rx_desc, unsigned int socket_id,
>>>>>>                     const struct rte_eth_rxconf *rx_conf,
>>>>>>                     struct rte_mempool *mp)
>>>>>>
>>>>>> int
>>>>>> rte_eth_link_get(uint16_t port_id, struct rte_eth_link *eth_link)
>>>>>>
>>>>>> int
>>>>>> rte_eth_stats_get(uint16_t port_id, struct rte_eth_stats *stats)
>>>>>>
>>>>>> int
>>>>>> rte_eth_dev_info_get(uint16_t port_id, struct rte_eth_dev_info *dev_info)
>>>>>>
>>>>>> As these APIs could be used by any APPs, if the APP give NULL as
>>>>>> the pointer parameter, segmetation default will occur.
>>>>>>
>>>>>> So, my question is, should we add check in the API? like that,
>>>>>> int rte_eth_stats_get(uint16_t port_id, struct rte_eth_stats *stats)
>>>>>> {
>>>>>>      if (stats == NULL)
>>>>>>              return -EINVAL;
>>>>>>      ...
>>>>>> }
>>>>>>
>>>>>> Or, that is redundant, the parameter correctness should be guaranteed by
>>>>>> the APP?
>>>>>>
>>>>>> What's your opinion? Hope for your reply.
>>>>> I remember it has been discussed in the past (many years ago),
>>>>> and the opinion was to not clutter the code for something that
>>>>> is a basic fault from the app.
>>>>>
>>>>> I don't have a strong opinion.
>>>>> What is your opinion? Others?
>>>> As I can see these are control path functions.
>>>> So some extra formal parameters check wouldn't hurt.
>>>> +1 from me to add them.
>>> +1 to add more sanity checks in control path APIs
>> +1
>> But are we going to check all parameters?
> 
> +1
> 
> It may be better to limit the number of checks.
> 

+1 to verify input for APIs.

Why not do all, what is the downside of checking all input for control path APIs?



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