svn commit: r316936 - head/sys/dev/cxgbe/iw_cxgbe

[Rodney W. Grimes]

> On Fri, Apr 14, 2017 at 06:15:10PM -0700, Rodney W. Grimes wrote:
> > [ Charset UTF-8 unsupported, converting... ]
> > > Author: np
> > > Date: Fri Apr 14 19:15:31 2017
> > > New Revision: 316936
> > > URL: https://svnweb.freebsd.org/changeset/base/316936
> > > 
> > > Log:
> > >   cxgbe/iw_cxgbe: hw supports 64K (not 32K) Protection Domains.
> > >   
> > >   MFC after:	3 days
> > >   Sponsored by:	Chelsio Communications
> > > 
> > > Modified:
> > >   head/sys/dev/cxgbe/iw_cxgbe/t4.h
> > > 
> > > Modified: head/sys/dev/cxgbe/iw_cxgbe/t4.h
> > > ==============================================================================
> > > --- head/sys/dev/cxgbe/iw_cxgbe/t4.h	Fri Apr 14 18:56:00 2017	(r316935)
> > > +++ head/sys/dev/cxgbe/iw_cxgbe/t4.h	Fri Apr 14 19:15:31 2017	(r316936)
> > > @@ -61,7 +61,7 @@
> > >  
> > >  #define T4_MAX_NUM_QP (1<<16)
> > >  #define T4_MAX_NUM_CQ (1<<15)
> > > -#define T4_MAX_NUM_PD (1<<15)
> > > +#define T4_MAX_NUM_PD 65536
> > 
> > Why the change in methods of expressing powers of 2 here?
> > This, imho, would better match the near by code as
> > #define	T4_MAX_NUM_PD (1<<16)
> > 
> 
> r316940 removed both of the 1<<foo lines above MAX_NUM_PD and all macros
> in this part of the header match nearby code:
> 
> #define T4_MAX_NUM_PD 65536
> #define T4_MAX_EQ_SIZE 65520
> #define T4_MAX_IQ_SIZE 65520
> #define T4_MAX_RQ_SIZE(n) (8192 - (n) - 1)
                                        ^^^ unexplained off by 1 Magic???

Ok, but why not code those as (1<<16), ((1<<16)-16)  to me it makes
it more clear as to what is going on here.  I suspect the -16 is
actually sizeof(something).  So even more clear is
to do something like:
#define X ((1<<16)-sizeof(somethingXreleated))

Magic constants like 65520 that dont even have a comment as to
why they are 65520 are in bad form as well.


-- 
Rod Grimes                                                 rgrimes at freebsd.org