[dpdk-dev] doc: deprecation notice for ethdev ops?

[Ferruh Yigit]

On 2/13/2017 5:21 PM, Dumitrescu, Cristian wrote:
> 
> 
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Monday, February 13, 2017 4:46 PM
>> To: Thomas Monjalon <thomas.monjalon at 6wind.com>; Dumitrescu, Cristian
>> <cristian.dumitrescu at intel.com>
>> Cc: dev at dpdk.org; Richardson, Bruce <bruce.richardson at intel.com>; Wiles,
>> Keith <keith.wiles at intel.com>
>> Subject: Re: [dpdk-dev] doc: deprecation notice for ethdev ops?
>>
>> On 2/13/2017 4:09 PM, Thomas Monjalon wrote:
>>> 2017-02-13 16:02, Dumitrescu, Cristian:
>>>> Hi Thomas,
>>>>
>>>> When a new member (function pointer) is added to struct eth_dev_ops
>> (as the last member), does it need to go through ABI chance process (e.g.
>> chance notice one release before)?
>>>>
>>>> IMO the answer is no: struct eth_dev_ops is marked as internal and its
>> instances are only accessed through pointers, so the rte_eth_devices array
>> should not be impacted by the ops structure expanding at its end. Unless
>> there is something that I am missing?
>>>
>>> You are right, it is an internal struct.
>>> So no need of a deprecation notice.
>>
>> When dpdk compiled as dynamic library, application will load PMDs
>> dynamically as plugin.
>> Is this use case cause ABI compatibility issue?
>>
>> I think drivers <--> libraries interface can cause ABI breakages for
>> dynamic library case, although not sure how common use case this is.
>>
> 
> Do you have a specific example that might cause an issue when adding a new function at the end of the ethdev ops structure? I cannot think of any, given that the ops structure is marked as internal and it is only accessed through pointers.

Adding at the end of the struct is probably safe.

> 
>>
>>>
>>> We must clearly separate API and internal code in ethdev.
>>>
>>>> My question is in the context of this patch under review for 17.5 release:
>> http://www.dpdk.org/ml/archives/dev/2017-February/057367.html.
>>>
>>> I did not look at it yet. Will do after the release.
>>>
>>>
>