Re: [PATCH] s390: Hypervisor File System

[Michael Holzheu <HOLZHEU@de.ibm.com>]

Hi Jörn,

Jörn Engel <joern@wohnheim.fh-wedel.de> wrote on 04/28/2006 11:43:20 AM:
> On Fri, 28 April 2006 11:22:25 +0200, Michael Holzheu wrote:
> > +
> > +static inline int info_blk_hdr__size(enum diag204_format type)
> > +{
> > +   if (type == INFO_SIMPLE)
> > +      return sizeof(struct info_blk_hdr);
> > +   else /* INFO_EXT */
> > +      return sizeof(struct x_info_blk_hdr);
> > +}
> > +
> > +static inline __u8 info_blk_hdr__npar(enum diag204_format type, void
*hdr)
> > +{
> > +   if (type == INFO_SIMPLE)
> > +      return ((struct info_blk_hdr *)hdr)->npar;
> > +   else /* INFO_EXT */
> > +      return ((struct x_info_blk_hdr *)hdr)->npar;
> > +}
> > +
> > +static inline __u8 info_blk_hdr__flags(enum diag204_format type, void
*hdr)
> > +{
> > +   if (type == INFO_SIMPLE)
> > +      return ((struct info_blk_hdr *)hdr)->flags;
> > +   else /* INFO_EXT */
> > +      return ((struct x_info_blk_hdr *)hdr)->flags;
> > +}
> > +
> > +static inline __u16 info_blk_hdr__pcpus(enum diag204_format type,void
*hdr)
> > +{
> > +   if (type == INFO_SIMPLE)
> > +      return ((struct info_blk_hdr *)hdr)->phys_cpus;
> > +   else /* INFO_EXT */
> > +      return ((struct x_info_blk_hdr *)hdr)->phys_cpus;
> > +}
>
> Hmm.  Another possible approach would be to create a small struct with
> a couple of functions, have one function each for type==INFO_SIMPLE
> and type==INFO_EXT and fill the struct either with one set of
> functions or the other.
>
> Whether that would make more sense than your current approach, I
> cannot judge.  Iirc, function calls are still fairly expensive on
> s390, so maybe not.
>

We discussed that! If we would have more than two data formats
we would have taken your approach. But for only two, I think
it is ok to do it my way!

Michael

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