Re: [dpdk-dev] [PATCH] librte_ether: use RTE_ETH_VALID_PORTID_OR_ERR_RET to check port_id

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2016-05-18 17:25, Mauricio Vásquez:
> On Wed, May 18, 2016 at 5:01 PM, Thomas Monjalon <thomas.monjalon@6wind.com>
> wrote:
> 
> > 2016-05-18 16:41, Mauricio Vásquez:
> > > On Wed, May 18, 2016 at 10:15 AM, Thomas Monjalon <
> > thomas.monjalon@6wind.com
> > > > wrote:
> > >
> > > > 2016-05-17 22:02, Mauricio Vásquez:
> > > > > On Fri, May 13, 2016 at 6:20 PM, Thomas Monjalon <
> > > > thomas.monjalon@6wind.com>
> > > > > wrote:
> > > > > > 2016-04-29 17:23, Mauricio Vasquez B:
> > > > > > > The RTE_ETH_VALID_PORTID_OR_ERR_RET macro is used in some places
> > > > > > > to check if a port id is valid or not. This commit makes use of
> > it in
> > > > > > > some new parts of the code.
> > > > > >
> > > > > > There are other occurences:
> > > > > >         rte_eth_dev_socket_id
> > > > > >
> > > > > I missed it.
> > > > >
> > > > > >         rte_eth_add_rx_callback
> > > > > >         rte_eth_add_tx_callback
> > > > > >         rte_eth_remove_rx_callback
> > > > > >         rte_eth_remove_tx_callback
> > > > > >
> > > > > The macro can not be used on those ones because they set the
> > rte_errno
> > > > > variable before returning.
> > > >
> > > > It may be a good idea to set rte_errno to EINVAL in these macros.
> > > >
> > > > Generally speaking, rte_errno is not used a lot currently.
> > >
> > >
> > > I noticed that both EINVAL and ENODEV are used. I think that returning
> > > ENODEV and setting rte_errno to EINVAL would be strange, what do you
> > think
> > > about always using ENODEV?
> >
> > Why EINVAL is used?
> >
> Why not using retval to set errno?
> >
> 
> If we do it, the macro could no be used in
>  rte_eth_dev_socket_id
>  rte_eth_dev_get_device_type
>  rte_eth_add_rx_callback
>  rte_eth_add_tx_callback
>  rte_eth_remove_rx_callback
>  rte_eth_remove_tx_callback
> as they do not return an error number.

So you should not set errno in the existing macro.
But you can create a new macro RTE_ETH_VALID_PORTID_OR_ERRNO_RET
for these functions.

> I feel ENODEV would be better but it is an API change, so we should discuss
> > it later for another patch.

It looks to be really needed to have an unique kind of error interface to
clean all this mess.