On Fri, Jun 7, 2019 at 1:23 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > On Fri, Jun 07, 2019 at 12:27:50PM -0700, Dan Williams wrote: > > diff --git a/lib/memregion.c b/lib/memregion.c > > new file mode 100644 > > index 000000000000..f6c6a94c7921 > > --- /dev/null > > +++ b/lib/memregion.c > > @@ -0,0 +1,15 @@ > > +#include <linux/idr.h> > > + > > +static DEFINE_IDA(region_ids); > > + > > +int memregion_alloc(gfp_t gfp) > > +{ > > + return ida_alloc(®ion_ids, gfp); > > +} > > +EXPORT_SYMBOL(memregion_alloc); > > + > > +void memregion_free(int id) > > +{ > > + ida_free(®ion_ids, id); > > +} > > +EXPORT_SYMBOL(memregion_free); > > Does this trivial abstraction have to live in its own file? I'd make > memregion_alloc/free static inlines that live in a header file, then > all you need do is find a suitable .c file to store memregion_ids in, > and export that one symbol instead of two. Ok, I think since these "memregion" objects tend to be closely related to "device memory" I'll stash this in kernel/memremap.c with the rest of the "ZONE_DEVICE" apis.