[systemd-devel] [PATCH] udev: Restore udevadm settle timeout

[David Herrmann]

Hi

On Sat, Apr 11, 2015 at 9:38 PM, Nir Soffer <nirsof at gmail.com> wrote:
> On Sat, Apr 11, 2015 at 1:36 PM, David Herrmann <dh.herrmann at gmail.com> wrote:
>> > @@ -139,6 +142,9 @@ static int adm_settle(struct udev *udev, int argc, char *argv[]) {
>> >                          break;
>> >                  }
>> >
>> > +                if (now(CLOCK_MONOTONIC) >= deadline)
>> > +                        break;
>> > +
>>
>> Previous udevadm allowed timeout=0 to disable this. I added the condition.
>
> Hi David,
>
> I think the handling of timeout=0 is incorrect now. The manual says:
>
>     A value of 0 will check if the queue is empty and always return
>     immediately.
>
> In udev-147 (used on rhel6), this was the behavior. If timeout was 0,
> is_timeout was set and settle was returning with rc=1.
>
> This behavior changed in:
>
> http://git.kernel.org/cgit/linux/hotplug/udev.git/commit/?id=ead7c62ab7641e150c6d668f939c102a6771ce60
>
> After this commit, zero timeout results in unlimited wait. Since this
> patch did not
> change the manual or the online help, and the commit message says:
> "udevadm: settle - kill alarm()", I guess this was unintended change.
>
> I don't see the use case for disabling the timeout, so it seems that
> we should fix
> this, restoring the behavior before this commit.
>
> What do you think?

Ok, this is on me, sorry for that. I tried to keep the behavior from
before the code-removal. I wasn't aware that this was not how it is
documented.

I'm actually not sure whether that was an intended change. It does not
look like it was, indeed. Maybe Kay or Tom know more.. I have no idea
whether timeout=0 is used in the wild.

I'll stall your further patches until we've decided on this.

Thanks
David