Re: [PATCH] net/tap: Bug fix to populate fds in secondary process

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/17/2022 6:33 PM, Thomas Monjalon wrote:
> 17/01/2022 19:28, Ferruh Yigit:
>>> +	ret = rte_eth_dev_get_port_by_name(request_param->port_name, &port_id);
>>> +	if (ret) {
>>> +		TAP_LOG(ERR, "Failed to get port id for %s",
>>> +			request_param->port_name);
>>> +		return -1;
>>> +	}
>>> +	dev = &rte_eth_devices[port_id];
>>
>> Since this is not really related with your patch, I want to have a separate thread for it.
>>
>> It is not good to access the 'rte_eth_devices' global variable directly from a driver, that
>> is error prone.
>>
>> Btw, what 'peer' supposed to contain?
>>
>> It can be solved by adding an internal API, only for drivers to get eth_dev from the name,
>> like: 'rte_eth_dev_get_by_name()'.
>> This way a few other usage can be converted to this API.
>>
>> @Thomas and @Andrew what do you think about the new API proposal?
> 
> It looks similar to rte_eth_dev_get_port_by_name() which returns a port_id.

Exactly, but get eth_dev directly for drivers. For drivers no need to work with port_id
handler, they can use eth_dev directly.

Another solution can be an getter function for drivers, which gets port_id and returns
the eth_dev.

> It is a bit strange for an ethdev driver to not have access to its own ethdev struct.
> Isn't there something broken in the logic?
> 

This is callback function between primary and secondary applications sync. So port name
will be same for both, but eth_dev will be different and port_id may be different.
Driver finds its own eth_dev from the shared port name.