On Wed, Jul 10, 2019 at 09:02:04PM +0200, Jan Kara wrote: > +#define DAX_ENTRY_CONFLICT dax_make_entry(pfn_to_pfn_t(1), DAX_EMPTY) I was hoping to get rid of DAX_EMPTY ... it's almost unused now. Once we switch to having a single DAX_LOCK value instead of a single bit, I think it can go away, freeing up two bits. If you really want a special DAX_ENTRY_CONFLICT, I think we can make one in the 2..4094 range. That aside, this looks pretty similar to the previous patch I sent, so if you're now happy with this, let's add #define XA_DAX_CONFLICT_ENTRY xa_mk_internal(258) to xarray.h and do it that way?