Wed, Sep 06, 2017 at 07:03:10AM CEST, xiyou.wangc...@gmail.com wrote:
>tcf_chain_destroy() is called by tcf_block_put() and tcf_chain_put().
>tcf_chain_put() is refcn'ed and paired with tcf_chain_get(),
>but tcf_block_put() is not, it should be paired with tcf_block_get()
>and we still need to decrease the refcnt. However, tcf_block_put()
>is special, it stores the chains too, we have to detach them if
>it is not the last user.
You don't describe the original issue, or I am missing that from your
description.
>
>What's more, index 0 is not special at all, it should be treated
>like other chains. This also makes the code more readable.
[...]
>@@ -246,10 +246,7 @@ EXPORT_SYMBOL(tcf_chain_get);
>
> void tcf_chain_put(struct tcf_chain *chain)
> {
>- /* Destroy unused chain, with exception of chain 0, which is the
>- * default one and has to be always present.
>- */
>- if (--chain->refcnt == 0 && !chain->filter_chain && chain->index != 0)
>+ if (--chain->refcnt == 0)
The refcounting is only done for actions holding reference to the chain.
You still need to check is the filter chain is not empty.
See tc_ctl_tfilter.
Also, chain 0 is created by default on a block creation. It has to be
present always for a reason. Please see tcf_block_get. The pointer to
chain 0 is assigned to the qdisc filter list pointer.
> tcf_chain_destroy(chain);
> }
> EXPORT_SYMBOL(tcf_chain_put);
>@@ -296,8 +293,11 @@ void tcf_block_put(struct tcf_block *block)
>
> list_for_each_entry_safe(chain, tmp, &block->chain_list, list) {
> tcf_chain_flush(chain);
>- tcf_chain_destroy(chain);
>+ tcf_chain_put(chain);
> }
>+ /* If tc actions still hold the chain, just detach it. */
>+ list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
>+ tcf_chain_detach(chain);
> kfree(block);
> }
> EXPORT_SYMBOL(tcf_block_put);
>--
>2.13.0
>
