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

[Zbigniew Jędrzejewski-Szmek]

On Mon, Apr 20, 2015 at 10:33:48AM +0200, David Herrmann wrote:
> 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.
What's the status here?

Zbyszek