Re: [Xen-devel] [PATCH 1/3] xen/mce: Add mcelog support for Xen platform (v2)

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

> >>>> -static struct miscdevice mce_chrdev_device = {
> >>>> +struct miscdevice mce_chrdev_device = {
> >>>>  	MISC_MCELOG_MINOR,
> >>>>  	"mcelog",
> >>>>  	&mce_chrdev_ops,
> >>> 
> >>> You're still reusing those - pls, define your own 'struct miscdevice
> >>> mce_chrdev_device' in drivers/xen/ or somewhere convenient and
> >>> your own mce_chrdev_ops. The only thing you should be touching in
> >>> arch/x86/.../mcheck/ is the export of MISC_MCELOG_MINOR.
> >>> 
> >>> Thanks.
> >> 
> >> I'm *not* reuse native code.
> >> I have defined 'struct miscdevice xen_mce_chrdev_device' in
> >> drivers/xen, and I also implement xen_mce_chrdev_ops, they are all
> >> xen-self-contained.  
> >> 
> >> The patch just redirect native mce_chrdev_device to
> >> xen_mce_chrdev_device when running under xen environment. 
> >> It didn't change any native code (except just cancel
> >> mce_chrdev_device 'static'), and will not break native logic. 
> > 
> > Why are you doing that?
> > 
> > Why don't you do
> > 
> > 	misc_register(&xen_mce_chrdev_device);
> > 
> > in xen_early_init_mcelog() ?
> > 
> > This way there'll be no arch/x86/ dependencies at all.
> 
> The reason is, if we do so, it would be covered by native misc_register(&mce_chrdev_device) later when native kernel init (xen init first and then start native kernel).

Won't the second registration (so the original one) of the major fail? So the mce_log
would just error out since somebody already registered?