hv_get_bytes_to_write
bytes_avail_towrite = hv_get_bytes_to_write(outring_info);
curr_write_sz = hv_get_bytes_to_write(rbi);
ret = sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi));
u32 avail_write = hv_get_bytes_to_write(rbi);
u32 writeable = hv_get_bytes_to_write(&chan->outbound);
if (hv_get_bytes_to_write(&chan->outbound) > 0)