Re: [Qemu-devel] [RFC v2 3/6] pci: Rename and change signatures of pci_bus_new() & related functions

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, Apr 19, 2017 at 09:50:01AM -0300, Eduardo Habkost wrote:
> On Wed, Apr 19, 2017 at 09:41:42AM +0100, Peter Maydell wrote:
> > On 18 April 2017 at 23:17, Eduardo Habkost <ehabkost@redhat.com> wrote:
> > > pci_bus_new*() and pci_register_bus() work only when the 'parent'
> > > argument is a PCI_HOST_BRIDGE object. Rename them to reflect that they
> > > are meant to initialize a bus that's in a PCI host bridge.
> > >
> > > The new function names are:
> > > * pci_host_bus_init() (replacing pci_bus_new())
> > > * pci_host_bus_init_inplace() (replacing pci_bus_new_inplace())
> > > * pci_host_bus_init_irqs() (replacing pci_register_bus())
> > 
> > This is moving these functions away from the convention that
> > we seem to mostly follow for buses (eg ISA, SCSI) of
> > foo_bus_new() to allocate and return a new bus, and
> > foo_bus_new_inplace() to initialize a bus that's inline in
> > some other struct.
> > 
> > I'm not sure this is a good idea unless we have a plan to
> > convert all the other QOM buses and document that this is
> > the right way to implement init for a bus.
> 
> The point of the rename is that those functions are doing more
> than just allocating a PCIBus. They do some initialization of
> PCIHostState as well. That's why non-root PCI buses can't be
> created by pci_bus_new*() today.

Hm, yeah.

So.. for what's now pci_register_bus() is it even worth keeping a
helper?  Could we just require that callers call the other init
function then call pci_bus_irqs().  That would be one less name to
come up with.

For the others, what about
	pci_common_root_bus_new()
	pci_common_root_bus_init_inplace()
?

> Maybe the answer here is to move the PCI_HOST_BRIDGE-specific
> code somewhere else, and make pci_bus_new*() more generic. This
> would allow us to reuse pci_bus_new*() when creating non-root PCI
> buses, later.

That might work even better.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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