On Mon, Feb 26, 2018 at 2:55 PM, David Ahern <dsah...@gmail.com> wrote:
> On 2/26/18 3:28 PM, Wei Wang wrote:
>>> @@ -213,11 +234,6 @@ static inline void rt6_set_expires(struct rt6_info
>>> *rt, unsigned long expires)
>>>
>>> static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
>>> {
>>> - struct rt6_info *rt;
>>> -
>>> - for (rt = rt0; rt && !(rt->rt6i_flags & RTF_EXPIRES); rt =
>>> rt->from);
>>> - if (rt && rt != rt0)
>>> - rt0->dst.expires = rt->dst.expires;
>>
>> I was wondering if we need to retain the above logic. It makes sure
>> dst.expires gets synced to its "parent" route. But it might be hard
>> because after your change, we can no longer use rt->from to refer to
>> the "parent".
>
> As I understand it, the FIB entries are cloned into pcpu, uncached and
> exception routes. We should never have an rt6_info that ever points back
> more than 1 level -- ie., the dst rt6_info points to a from representing
> the original FIB entry.
>
Yes. Agree.
> After my change 'from' will still point to the FIB entry as a fib6_info
> which has its own expires.
>
understood. And fib6_age() is using fib6_check_expired() and
rt6_age_exceptions() is checking rt->dst.expires which I think is
correct.
> When I looked this code I was really confused. At best, the for loop
> above sets rt0->dst.expires to some value based on the 'from' but then
> the very next line calls dst_set_expires with the passed in timeout value.
>
>
>>
>>> dst_set_expires(&rt0->dst, timeout);
>>> rt0->rt6i_flags |= RTF_EXPIRES;
>>> }
>
