diff options
| -rw-r--r-- | net/sched/cls_api.c | 47 |
1 files changed, 26 insertions, 21 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index c743f03cfebd..d29e79d98a69 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -182,7 +182,7 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block *block, list_add_tail(&chain->list, &block->chain_list); chain->block = block; chain->index = chain_index; - chain->refcnt = 0; + chain->refcnt = 1; return chain; } @@ -194,21 +194,20 @@ static void tcf_chain_flush(struct tcf_chain *chain) RCU_INIT_POINTER(*chain->p_filter_chain, NULL); while ((tp = rtnl_dereference(chain->filter_chain)) != NULL) { RCU_INIT_POINTER(chain->filter_chain, tp->next); + tcf_chain_put(chain); tcf_proto_destroy(tp); } } static void tcf_chain_destroy(struct tcf_chain *chain) { - /* May be already removed from the list by the previous call. */ - if (!list_empty(&chain->list)) - list_del_init(&chain->list); + list_del(&chain->list); + kfree(chain); +} - /* There might still be a reference held when we got here from - * tcf_block_put. Wait for the user to drop reference before free. - */ - if (!chain->refcnt) - kfree(chain); +static void tcf_chain_hold(struct tcf_chain *chain) +{ + ++chain->refcnt; } struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index, @@ -217,24 +216,19 @@ struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index, struct tcf_chain *chain; list_for_each_entry(chain, &block->chain_list, list) { - if (chain->index == chain_index) - goto incref; + if (chain->index == chain_index) { + tcf_chain_hold(chain); + return chain; + } } - chain = create ? tcf_chain_create(block, chain_index) : NULL; -incref: - if (chain) - chain->refcnt++; - return chain; + return create ? tcf_chain_create(block, chain_index) : NULL; } 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) tcf_chain_destroy(chain); } EXPORT_SYMBOL(tcf_chain_put); @@ -279,10 +273,19 @@ void tcf_block_put(struct tcf_block *block) if (!block) return; + /* XXX: Standalone actions are not allowed to jump to any chain, and + * bound actions should be all removed after flushing. However, + * filters are destroyed in RCU callbacks, we have to flush and wait + * for them inside the loop, otherwise we race with RCU callbacks on + * this list. + */ list_for_each_entry_safe(chain, tmp, &block->chain_list, list) { tcf_chain_flush(chain); - tcf_chain_destroy(chain); + rcu_barrier(); } + + list_for_each_entry_safe(chain, tmp, &block->chain_list, list) + tcf_chain_put(chain); kfree(block); } EXPORT_SYMBOL(tcf_block_put); @@ -360,6 +363,7 @@ static void tcf_chain_tp_insert(struct tcf_chain *chain, rcu_assign_pointer(*chain->p_filter_chain, tp); RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info)); rcu_assign_pointer(*chain_info->pprev, tp); + tcf_chain_hold(chain); } static void tcf_chain_tp_remove(struct tcf_chain *chain, @@ -371,6 +375,7 @@ static void tcf_chain_tp_remove(struct tcf_chain *chain, if (chain->p_filter_chain && tp == chain->filter_chain) RCU_INIT_POINTER(*chain->p_filter_chain, next); RCU_INIT_POINTER(*chain_info->pprev, next); + tcf_chain_put(chain); } static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain, |