-/*
- * A cardmap represents a mapping from unsigned integers to pointers,
- * and provides a fast "find lowest unused number" operation.
- * It uses a broad (32-way) tree with a bitmap at each level.
- * It is designed to be space-efficient for small numbers of entries
- * and time-efficient for large numbers of entries.
- */
-#define CARDMAP_ORDER 5
-#define CARDMAP_WIDTH (1U << CARDMAP_ORDER)
-#define CARDMAP_MASK (CARDMAP_WIDTH - 1)
-
-struct cardmap {
- int shift;
- unsigned long inuse;
- struct cardmap *parent;
- void *ptr[CARDMAP_WIDTH];
-};
-static void *cardmap_get(struct cardmap *map, unsigned int nr);
-static void cardmap_set(struct cardmap **map, unsigned int nr, void *ptr);
-static unsigned int cardmap_find_first_free(struct cardmap *map);
-static void cardmap_destroy(struct cardmap **map);
-
-/*
- * all_ppp_mutex protects the all_ppp_units mapping.
- * It also ensures that finding a ppp unit in the all_ppp_units map
- * and updating its file.refcnt field is atomic.
- */
-static DEFINE_MUTEX(all_ppp_mutex);
-static struct cardmap *all_ppp_units;