Ok, that simplifies things, at least we can call
tty->ops->wait_until_sent(tty, timeout) while holding
the BTM then, even with the next patch that makes it
non-recursive.
These, and most of the others in this patch call tty_wait_until_sent()
from their close() function. That contains the lines
if (wait_event_interruptible_timeout(tty->write_wait,
!tty_chars_in_buffer(tty), timeout) >= 0) {
Part of what my patch does is to give up the BTM when already
holding it, to mimic the BKL behavior.
If you can confirm that this wait_event never blocks indefinitely
or has to wait for the BTM from another function, that could just
be removed. Otherwise, it probably needs to become something ugly
like
if (tty_chars_in_buffer(tty)) {
if (tty_locked()) {
tty_unlock();
wait = wait_event_interruptible_timeout(tty->write_wait,
!tty_chars_in_buffer(tty), timeout) >= 0);
tty_lock();
} else {
wait = wait_event_interruptible_timeout(tty->write_wait,
!tty_chars_in_buffer(tty), timeout) >= 0);
}
if (wait && tty->ops->wait_until_sent)
tty->ops->wait_until_sent(tty, timeout);
}
I already had to introduce a few of these constructs to make the BTM
non-recursive, but I'd prefer to keep the number as low as possible
for obvious reasons.
Fine with me.
While I technically own a 16-port specialix card somewhere in my
parents' basement, I'm not exactly interested in maintaining the
driver.
Arnd
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