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

[Harald Hoyer]

On 20.04.2015 10:33, 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.
> 


Oh, dracut makes use of "udevadm settle --timeout=0" all the time