On Fri 07 Sep 2018 at 19:12, Cong Wang <xiyou.wangc...@gmail.com> wrote: > On Fri, Sep 7, 2018 at 6:52 AM Vlad Buslov <vla...@mellanox.com> wrote: >> >> Action API was changed to work with actions and action_idr in concurrency >> safe manner, however tcf_del_walker() still uses actions without taking a >> reference or idrinfo->lock first, and deletes them directly, disregarding >> possible concurrent delete. >> >> Add tc_action_wq workqueue to action API. Implement >> tcf_idr_release_unsafe() that assumes external synchronization by caller >> and delays blocking action cleanup part to tc_action_wq workqueue. Extend >> tcf_action_cleanup() with 'async' argument to indicate that function should >> free action asynchronously. > > Where exactly is blocking in tcf_action_cleanup()? > > From your code, it looks like free_tcf(), but from my observation, > the only blocking function inside is tcf_action_goto_chain_fini() > which calls __tcf_chain_put(). But, __tcf_chain_put() is blocking > _ONLY_ when tc_chain_notify() is called, for tc action it is never > called. > > So, what else is blocking?
__tcf_chain_put() calls tc_chain_tmplt_del(), which calls ops->tmplt_destroy(). This last function uses hw offload API, which is blocking.
