[dpdk-dev] [PATCH 2/2] drivers/net: use device name from device structure

[Ferruh Yigit]

On 6/10/2017 8:35 AM, Jan Blunck wrote:
> On Fri, Jun 9, 2017 at 3:52 PM, Thomas Monjalon <thomas at monjalon.net> wrote:
>> 26/05/2017 18:11, Ferruh Yigit:
>>> Device name resides in two different locations, in rte_device->name and
>>> in ethernet device private data.
>>
>> Yes would be nice to remove the name from rte_eth_dev_data.
>>
> 
> I wonder if this is really the right thing to do. The name in the
> eth_dev data is the eth_dev device name and it might be different from
> the low-level device name. Some busses might use UUID as the device
> identifier and I don't believe that this is a user friendly name.

Right now eth_dev->data->name is same with with rte_dev->device->name.
And there is an assumption that they will be same [1].

But if you think they can be different in the future, I think we can:
1- Keep as it is.
2- Reduce to single variable as much as possible (this patch), when
different naming implemented, update relevant parts according. Since
this is internal structure, I believe won't cause an ABI issue.


[1]
rte_eth_dev_pci_allocate() and rte_eth_vdev_allocate() use
rte_dev->device->name to call rte_eth_dev_allocate(), which inside calls
rte_eth_dev_allocated() with same name. Which assumes any previously
created eth_dev, created with rte_dev->device->name.

> 
>>> For now, the copy in the ethernet device private data is required for
>>> multi process support, the name is the how secondary process finds about
>>> primary process device.
>>
>> Yes it is in rte_eth_dev_attach_secondary().
>> This secondary process forces us to write ugly data structures.
>>
>>> But for drivers there is no reason to use the copy in the ethernet
>>> device private data.
>>
>> Yes I agree.
> 
> Probably. But it also depends on at what stage the driver is using the
> name and what information is printed. During probing I would expect
> the low-level device name to be printed. After probing the eth_dev PMD
> should use the user friendly device name.

This makes sense when different naming used for core device and eth_dev,
but this is not the case for now.

> 
>> There are probably other places where we can avoid using this field.
>> I see rte_eth_dev_get_name_by_port() and rte_eth_dev_get_port_by_name()
>> using rte_eth_dev_data[port].name.
>>
>>> This patch updates PMDs to use only rte_device->name.
>>>
>>> Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
>>