[dm-devel] [PATCH v3 3/5] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()

[Andrew Morton]

On Mon, 18 Jun 2018 15:01:43 -0700 Dmitry Torokhov <dmitry.torokhov at gmail.com> wrote:

> > > +unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
> > > +{
> > > +     return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long), flags);
> > > +}
> > > +EXPORT_SYMBOL(bitmap_alloc);
> > > +
> > > +unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
> > > +{
> > > +     return bitmap_alloc(nbits, flags | __GFP_ZERO);
> > > +}
> > > +EXPORT_SYMBOL(bitmap_zalloc);
> > > +
> > > +void bitmap_free(const unsigned long *bitmap)
> > > +{
> > > +     kfree(bitmap);
> > > +}
> > > +EXPORT_SYMBOL(bitmap_free);
> > > +
> >
> > I suggest these functions are small and simple enough to justify
> > inlining them.
> >
> 
> We can't as we end up including bitmap.h (by the way of cpumask.h)
> form slab.h, so we gen circular dependency.

That info should have been in the changelog, and probably a code
comment.

> Maybe if we removed memcg
> stuff from slab.h so we do not need to include workqueue.h...

Or move the basic slab API stuff out of slab.h into a new header.  Or
create a new, standalone work_struct.h - that looks pretty simple.