On Tue, Sep 01, 2015 at 01:38:02PM +0000, Iremonger, Bernard wrote:
> Hi Neil, Thomas,
>
> <snip>
>
> > > You didn't remove the relationship of the ethdev to the pci driver
> > > though, which is really the problem, An ethdev may reside on any
> > > number of bus types (pci/usb/vmbus/virt/none).
>
> <snip>
>
> > > Whats really needed is a way to associate an ethdev with an arbitrary bus
>
> <snip>
>
> > > > Please see email below from 6Wind
> > > >
> > > > http://dpdk.org/ml/archives/dev/2015-July/022107.html
> > > >
> > > I think you misread that. I think all Thomas is asking for (correct
> > > me if I'm wrong Thomas), is for someone to start refactoring the
> > > ethdev registration code so that we can have a single init path
> > > without the need for wierd typing and differentiation at init time.
>
> <snip >
>
> > > We just need to
> > > start thinking about how to make bus registration independent of
> > > ethernet device registration, and while your patch series sort of
> > > eliminates some of that, its really not a proper refactoring of the
> > > sort I think Thomas is asking for.
>
> I am just trying to distill what the actual requirement is from the above
> discussion.
>
> (1) Remove relationship of the ethdev to the pci driver.
Correct
> (2) Refactor ethdev registration code so that there is a single init path.
Correct (or mostly correct, in rereading my initial post, there may be some
ambiguitiy here)
> (3) Make bus registration independent of ethdev registration.
Correct
> (4) Change all (17) PMD's to use the modified structures.
>
Correct (I assume the 17 number is accurate here)
> The rte_eal_driver_registration() code is in librte_eal, untouched as yet
> by this patch set.
>
Correct, the code that registers an init function is a single path, which is
great. However, that path requires that you specify a device type (in this case
PMD_PDEV or PMD_VDEV to differentiate pci vs virtual devices (it uses this for
ordering of initalization in rte_eal_dev_init, which is a hack). What would be
preferred would be if the structure that was registered via that macro only held
a name and an init routine to initalize the driver itself. Inside that init
routine, the driver would then be responsible for registering with the
appropriate bus type (virtual/pci/usb/whatever). A secondary function would be
registered as part of that process (akin to the linux/bsd probe() method) which
was called once for each instance of the device found on that bus.
> The rte_eth_driver_registration() code is in librte_ether.
> Should the pci fields be removed from the struct rte_eth_dev{} and struct
> eth_driver{},
IMO, yes, they should, as the driver can store pointers to those devices in
their private per-device data area. That said, there may be value in including
a union of all bus types in the ethdev itself, if there are higher layer
functions that need to be aware of a given ethdevs bus type
> and put somewhere else or replaced with a union of bus types and drivers?
>
> Regards,
>
> Bernard.
>
>
>
