LINE_BUFSIZE
end = line->buffer + LINE_BUFSIZE - line->tail;
count = line->buffer + LINE_BUFSIZE - line->head;
return LINE_BUFSIZE - 1;
n += LINE_BUFSIZE; /* The other case */
ret = LINE_BUFSIZE - (write_room(line) + 1);
line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);