esballoc_wait
mp = esballoc_wait(buf, size, BPRI_MED, &fdbuf->fd_frtn);
mp = esballoc_wait((uchar_t *)bp->b_un.b_addr + cmd->cmd_offset,
req->bulk_data = esballoc_wait(
extern mblk_t *esballoc_wait(unsigned char *, size_t, uint_t, frtn_t *);