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Diffstat (limited to 'net/sched/cls_api.c')
-rw-r--r--net/sched/cls_api.c47
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,