MAX_LOCKDEP_KEYS_BITS
#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
#define KEYHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
BUILD_BUG_ON(MAX_LOCKDEP_KEYS_BITS + 2 > 16);
return (hlock->class_idx | (hlock->read << MAX_LOCKDEP_KEYS_BITS));