[dpdk-dev] Clarification for eth_driver changes

Shreyansh Jain shreyansh.jain at nxp.com
Thu Nov 10 09:38:38 CET 2016


On Thursday 10 November 2016 01:21 PM, Jianbo Liu wrote:
> On 10 November 2016 at 15:26, Shreyansh Jain <shreyansh.jain at nxp.com> wrote:
>> Hello David, list,
>>
>> I need some help and clarification regarding some changes I am doing to
>> cleanup the EAL code.
>>
>> There are some changes which should be done for eth_driver/rte_eth_device
>> structures:
>>
>> 1. most obvious, eth_driver should be renamed to rte_eth_driver.
>> 2. eth_driver currently has rte_pci_driver embedded in it
>>  - there can be ethernet devices which are _not_ PCI
>>  - in which case, this structure should be removed.
>> 3. Similarly, rte_eth_dev has rte_pci_device which should be replaced with
>> rte_device.
>>
>> This is what the current outline of eth_driver is:
>>
>> +------------------------+
>> | eth_driver             |
>> | +---------------------+|
>> | | rte_pci_driver      ||
>> | | +------------------+||
>> | | | rte_driver       |||
>> | | |  name[]          |||
>> | | |  ...             |||
>> | | +------------------+||
>> | |  .probe             ||
>> | |  .remove            ||
>> | |  ...                ||
>> | +---------------------+|
>> |  .eth_dev_init         |
>> |  .eth_dev_uninit       |
>> +------------------------+
>>
>> This is what I was thinking:
>>
>> +---------------------+        +----------------------+
>> | rte_pci_driver      |        |eth_driver            |
>> | +------------------+|       _|_struct rte_driver *p |
>> | | rte_driver       <-------/ | .eth_dev_init        |
>> | |  ...             ||        | .eth_dev_uninit      |
>> | |  name            ||        +----------------------+
>> | |  <more>          ||
>> | +------------------+|
>> |  <PCI specific info>|
>> +---------------------+
>>
>> ::Impact::
>> Various drivers use the rte_pci_driver embedded in the eth_driver object for
>> device initialization.
>>  == They assume that rte_pci_driver is directly embedded and hence simply
>> dereference.
>>  == e.g. eth_igb_dev_init() in drivers/net/e1000/igb_ethdev.c file
>>
>> With the above change, such drivers would have to access rte_driver and then
>> perform container_of to obtain their respective rte_xxx_driver.
>>  == this would be useful in case there is a non-PCI driver
>>
>> ::Problem::
>> I am not sure of reason as to why eth_driver embedded rte_pci_driver in
>> first place - other than a convenient way to define it before PCI driver
>> registration.
>>
>> As all the existing PMDs are impacted - am I missing something here in
>> making the above change?
>>
>
> How do you know eth_driver->p is pointing to a rte_pci_driver or rte_soc_driver?
> Maybe you need to add a type/flag in rte_driver.

My take: PMD implementation would specify this - similar to how it is 
done now. A PCI PMD would perform a container_of(rte_pci_driver,...).
I don't think we need a differentiation here - primarily because 
generic doesn't handle the eth_driver.

>
>> Probably, similar is the case for rte_eth_dev.
>>
>> -
>> Shreyansh
>


-- 
-
Shreyansh


More information about the dev mailing list