BITS_TO_LONGS_COMPAT
len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);