Re: [kvm-unit-tests PATCH v4 9/9] s390x: sclp: Add CPU entry offset comment

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 13 Jan 2021 11:25:45 +0100
David Hildenbrand <david@redhat.com> wrote:

> On 12.01.21 14:20, Janosch Frank wrote:
> > Let's make it clear that there is something at the end of the
> > struct. The exact offset is reported by the cpu_offset member.
> > 
> > Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> > ---
> >  lib/s390x/sclp.h | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
> > index dccbaa8..395895f 100644
> > --- a/lib/s390x/sclp.h
> > +++ b/lib/s390x/sclp.h
> > @@ -134,7 +134,10 @@ typedef struct ReadInfo {
> >  	uint8_t reserved7[134 - 128];
> >  	uint8_t byte_134_diag318 : 1;
> >  	uint8_t : 7;
> > -	struct CPUEntry entries[0];
> > +	/*
> > +	 * The cpu entries follow, they start at the offset specified
> > +	 * in offset_cpu.
> > +	 */  
> 
> I mean, that's just best practice. At least when I spot "[0];" and the
> end of a struct, I know what's happening.

Agreed.

> 
> No strong opinion about the comment, I wouldn't need it to understand it.

I'd keep it as-is; maybe add a comment where offset_cpu points to?

> 
> >  } __attribute__((packed)) ReadInfo;
> >  
> >  typedef struct ReadCpuInfo {
> >   
> 
>