On Wed, Jan 13, 2016 at 03:12:27PM +0100, Jan Viktorin wrote:
> On Wed, 13 Jan 2016 14:01:19 +0000
> Bruce Richardson <bruce.richardson at intel.com> wrote:
>
> > On Mon, Jan 04, 2016 at 09:08:15PM +0100, Jan Viktorin wrote:
> > > The union rte_device can be used in situations where we want to work with
> > > all
> > > devices without distinguishing among bus-specific features (PCI, ...).
> > > The target device type can be detected by reading the magic.
> > >
> > > Also, the macros RTE_DEVICE_DECL and RTE_DEVICE_PTR_DECL are introduced to
> > > provide a generic way to declare a device or a pointer to a device. The
> > > macros
> > > aim to preserve API backwards-compatibility. Eg.
> > >
> > > struct old_super_struct { => struct old_super_struct {
> > > struct rte_pci_device *pci_dev; =>
> > > RTE_DEVICE_PTR_DECL(pci_dev);
> > > ... => ...
> > > }; => };
> > >
> > > struct old_super_struct inst;
> > >
> > > The new code should reference inst.dev.pci, the old code can still use the
> > > inst.pci_dev. The previously introduced magic is included so one can ask
> > > the
> > > instance about its type:
> > >
> > > if (inst.dev.magic == RTE_PCI_DEVICE_MAGIC) {
> > > ...
> > > }
> >
> > Rather than magic numbers i.e. #defines, an enum might be better.
>
> True. However, would it be helpful to put really some _magic_ numbers
> there for debugging purposes (to clearly recognize the data type)? Or,
> is it sufficient to just say 1 for PCI, 2 for SoC, 3 for xxx...?
>
I'd find it hard to see the need for actual magic numbers. I think the magic
field
should be renamed to "type" and the values taken from a device_type enum. Should
make the code more readable e.g.
if (inst.dev.type == RTE_DEVTYPE_PCI) { ... }
/Bruce
