Re: [PATCH 01/02] cpuset bitmap and mask remap operators

[Andrew Morton <akpm@osdl.org>]

Paul Jackson <pj@sgi.com> wrote:
>
> Andrew wrote:
> > >  +#define node_remap(oldbit, old, new) \
> > >  +		__node_remap((oldbit), &(old), &(new), MAX_NUMNODES)
> > >  +static inline int __node_remap(int oldbit, ...
> >
> > What's the reason for the wrapper macro?
> 
> Most all the nodemask/cpumask operators are like that.  It allows
> writing *mask code as if masks were pass by value (which is how the
> vast majority of kernel hackers, working on systems with one-word
> masks, think of them), while actually passing by reference, to
> avoid unnecessary stack copies of multiword masks.
> 

hm.  That hides what's really going on from the programmer.

Oh well - you're the only guy who dinks with that stuff anyway ;)

> > +EXPORT_SYMBOL(bitmap_bitremap);
> > 
> > Is that deliberately not EXPORT_SYMBOL_GPL?
> 
> It's not deliberate that I am aware of.
> 
> But it does seem to be the common practice ....
> 
> All the bitmap routines are that way - no GPL.  In fact it seems that
> almost all the EXPORT_SYMBOLS in the lib/*.c routines are that way - 12
> with GPL and 174 without GPL, or some such.  The only lib/*.c GPL
> exports are in lib/klist.c and lib/kobject_uevent.c.
> 
> Is this bad?
> 

Ah, the bitmap library - sorry I thought it was in the cpuset code.

Making the bitmap library non-GPL makes sense I guess.