Thomas Graf wrote:
The handling of a failure in tcf_bind_filter is inconsistent.
u32: ignore
fw: ignore
route: ignore
rsvp: ignore
tcindex: error
It might be a good idea to make this consistent. So in order to validate
the classid before making any changes we could simply lock it via get
(see patch below), return an error if it fails and put it back in case
of an error further in the path or after binding the filter.
Bindings not only locks the class from removal while a filter is
pointing to it. It speeds up classyfing by saving a lookup for every
tc_classify call. It's not really a problem if the class is not locked,
the qdisc will look it up and falls back to a default class if it
doesn't exists so it's rather a cosmetic/policy thing.
You should just fix tcindex not to care about errors in tcf_bind_filter.
bind_tcf already locks the class. Some qdiscs (like prio) map bind_filter
to get, but others (HTB, HFSC, CBQ) use a seperate counter because it is
legal to end up with a refcnt > 0 after delete. When a class with filters
pointing to it is tried to destroy they return -EBUSY, which can't be done
by looking at the refcnt.
Regards
Patrick
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