* Patrick McHardy <41BDDB5A.9000907@xxxxxxxxx> 2004-12-13 19:11
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.
Little misunderstanding here. I'm not aiming at replacing tcf_bind_filter
with get. My question is rather whether to regard tcf_bind_filter not setting
tcf_result->class as an error or ignore it.
I'm all for ignoring it in tcindex, it requires some changes because
it checks tcf_result.class field to see if hash bucket is non-empty if
perfect hash is used but is not a problem at all.
The tcf_class_get/put would be required to ensure proper locking during
validation of parameters if validating the classid being last before
changing things doesn't make sense due to the need to undo expensive
operations required before binding.
I will fix tcindex, since you also agree on simply ignoring it and regard
the binding as an ptional locking and performance increase possibility
given to userspace.