On 2019/01/04 0:57, Paul Fulghum wrote: >> On Jan 3, 2019, at 3:32 AM, Tetsuo Handa >> <penguin-ker...@i-love.sakura.ne.jp> wrote: >> >> On 2019/01/03 18:09, Jiri Slaby wrote: >>> On 02. 01. 19, 16:04, Tetsuo Handa wrote: >>>> + if (wait_event_interruptible(tty->read_wait, >>>> + (ret = -EIO, test_bit(TTY_OTHER_CLOSED, &tty->flags)) || >>>> + (ret = 0, tty_hung_up_p(file)) || >>>> + (rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)) != NULL || >>>> + (ret = -EAGAIN, tty_io_nonblock(tty, file)))) >>>> + return -EINTR; >>> >>> Oh, that looks really ugly. Could you move all this to a function >>> returning a bool and taking &ret and &rbuf as parameters? >>> >> >> OK. Something like this? > > > I agree with Jiri that placing all the conditional logic in a single > expression is difficult to read. > > But exchanging that many locals with a separate function defeats the original > purpose of > simplifying code and this implementation changes the logic (write no > longer checks for line discipline changing under it during wait).
Not only defeating the original purpose but also increasing object size. > > Converting to wait_event_interruptible where possible is a good goal but this > instance > may be better left alone. The current structure mirrors the existing n_tty > line discipline. But why not to clarify what are appropriate sanity checks? Currently, read side does not check "n_hdlc->magic != HDLC_MAGIC" case while write side does. If it is intended for catching memory corruption etc. then both sides should do the same thing. Currently, write side does not check "tty != n_hdlc->tty" case before schedule() while does after schedule(). If "tty != n_hdlc->tty" case can ever happen, what prevents n_hdlc_tty_write() from being called again after n_hdlc_tty_write() once returned with -EIO due to "tty != n_hdlc->tty" case? If it is intended for catching memory corruption etc. then both sides should check "tty != n_hdlc->tty" case. Current logic is unclear, in addition to want a cleanup for scripts/checkpatch.pl . total: 158 errors, 95 warnings, 994 lines checked
