free_px
free_px(vm, &pd->pt, lvl);
free_px(vm, pt, lvl);
void free_px(struct i915_address_space *vm,
#define free_pt(vm, px) free_px(vm, px, 0)
#define free_pd(vm, px) free_px(vm, px_pt(px), 1)
free_px(vm, pt, n);