Re: [PATCH] Some function locals in udev_rules_parse.c were needlessly

[Alan Jenkins <alan-jenkins@tuffmail.co.uk>]

Kay Sievers wrote:
> On Sun, Aug 31, 2008 at 19:30, Alan Jenkins <alan-jenkins@tuffmail.co.uk> wrote:
>   
>> This does not affect current behaviour.  However, it is required to
>> make the functions thread-safe.  (I'm playing with a threaded udevd).
>>     
>
>   
>> -       static struct udev_rule *rule;
>> +       struct udev_rule *rule;
>>     
>
> It's not needlessly static, we return _this_ value. The parsing stuff
> is not thread safe at the moment, we would need a real fix, this would
> break it.
>   
Thanks for looking at these patches.

The functions do "return rule", but they always write to it before
reading it, so there's no persistent state here.  And they don't "return
&rule", so it's fine for the variable to be on the stack.  Did I miss
something?

I belatedly noticed the other parsing stuff a few hours after posting
the patch :-).  I hacked it up and (with unpublished patches) finally
got a threaded udevd which appeared to work.  (I also did per-thread
environment variable emulation, and fixed the caches in udev_sysfs.c for
thread-safety).  So empirically I had judged this patch correct.  And my
unpublished patches wouldn't conflict with or obsolete this one.

Regards
Alan