Re: [PATCH 5/5] vsprintf: Make %pGp print the hex value

[Petr Mladek <pmladek@suse.com>]

On Fri 2021-10-15 12:55:48, Petr Mladek wrote:
> On Tue 2021-10-12 19:26:47, Matthew Wilcox (Oracle) wrote:
> > All existing users of %pGp want the hex value as well as the decoded
> > flag names.  This looks awkward (passing the same parameter to printf
> > twice), so move that functionality into the core.  If we want, we
> > can make that optional with flag arguments to %pGp in the future.
> 
> It makes sense. Just the selftest code is pain, see below ;-)
> 
> > diff --git a/lib/test_printf.c b/lib/test_printf.c
> > index 662c3785aa57..a60b1a749e87 100644
> > --- a/lib/test_printf.c
> > +++ b/lib/test_printf.c
> > @@ -613,6 +613,10 @@ page_flags_test(int section, int node, int zone, int last_cpupid,
> >  	bool append = false;
> >  	int i;
> >  
> > +	for (i = 0; i < ARRAY_SIZE(values); i++)
> > +		page_flags |= (values[i] & pft[i].mask) << pft[i].shift;
> 
> I can't get the idea behind this. IMHO, the value might be zero even
> when the related flag is set.
> 
> And the %pGp code seems to always print page flags from
> page_flags_fields[] when the field width is not zero.
> 
> Or do I misread the code?

Just for record. I really did misread the code. It constructs flags
from the given values. It does reverse operation to
format_page_flags().

Best Regards,
Petr