The find_fit function in this initial version is the same as the practic problem in chapter 10:

static void *find_fit(size_t asize)
{
    void *bp;

    /* first fit search */
    for (bp = heap_listp; GET_SIZE(HDRP(bp)) > 0; bp = NEXT_BLKP(bp)) {
        if (!GET_ALLOC(HDRP(bp)) && (asize <= GET_SIZE(HDRP(bp)))) {
            return bp;
        }
    }
    return NULL; /* no fit */
}