[dpdk-dev] stats_get API: return value suggestion

[Matan Azrad]

Hi All

Following the next thread:
http://dpdk.org/ml/archives/dev/2017-September/074032.html

The stats_get dev ops API doesn't include return value, so PMD cannot return error
in case of failure at stats getting process time.

Since PCI devices can be removed and there is a long time between the physical removing to the
remove interrupt callback completion, the user can get invalid stats without any indication.
(think about HW counter stats)

I suggest return value for this API - ENODEV\0.

It can be also relevant to stats_reset, promiscuous_enable\disable, allmulticast_enable\disable, etc...

What do you think?

Regards
Matan Azrad