On 15.08.23 03:02, Dan Drown wrote:
On Mon, 14 Aug 2023 14:32:57 +0200 Oliver Neukum oneukum@xxxxxxxx said
On 06.08.23 04:26, Dan Drown wrote:
> This patch adds support for PPS to CDC devices. Changes to the DCD pin
> are monitored and passed to the ldisc system, which is used by
> pps-ldisc.
do we really want to do this with acm>read_lock held?
Looks like it was put there to protect the iocount changes in the surrounding code. Are your concerns around performance or deadlocks?
Hi,
the lock is there for that and so that wait_serial_change()
will read consistent counts.
The latter concerns me. We are calling potentially arbitrary code. That
you intend it for PPS doesn't change that we'll call it for
every line discipline that supports that callback.
Line disciplines are supposed to do something with tty devices,
aren't they? So what methods could they call in turn?
Something that can end in wait_serial_change()?
Regards
Oliver
