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authorCong Wang <xiyou.wangcong@gmail.com>2017-10-26 18:24:28 -0700
committerDavid S. Miller <davem@davemloft.net>2017-10-29 22:49:30 +0900
commit7aa0045dadb6ef37485ea9f2a7d28278ca588b51 (patch)
treee3c535a5d93bef05b780d64e220039f360e19104 /include/net
parent8c83c88584abb3a04a4026be91060bc309f4c034 (diff)
net_sched: introduce a workqueue for RCU callbacks of tc filter
This patch introduces a dedicated workqueue for tc filters so that each tc filter's RCU callback could defer their action destroy work to this workqueue. The helper tcf_queue_work() is introduced for them to use. Because we hold RTNL lock when calling tcf_block_put(), we can not simply flush works inside it, therefore we have to defer it again to this workqueue and make sure all flying RCU callbacks have already queued their work before this one, in other words, to ensure this is the last one to execute to prevent any use-after-free. On the other hand, this makes tcf_block_put() ugly and harder to understand. Since David and Eric strongly dislike adding synchronize_rcu(), this is probably the only solution that could make everyone happy. Please also see the code comments below. Reported-by: Chris Mi <chrism@mellanox.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Pirko <jiri@resnulli.us> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/pkt_cls.h3
-rw-r--r--include/net/sch_generic.h2
2 files changed, 5 insertions, 0 deletions
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index e80edd8879ef..3009547f3c66 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -2,6 +2,7 @@
#define __NET_PKT_CLS_H
#include <linux/pkt_cls.h>
+#include <linux/workqueue.h>
#include <net/sch_generic.h>
#include <net/act_api.h>
@@ -17,6 +18,8 @@ struct tcf_walker {
int register_tcf_proto_ops(struct tcf_proto_ops *ops);
int unregister_tcf_proto_ops(struct tcf_proto_ops *ops);
+bool tcf_queue_work(struct work_struct *work);
+
#ifdef CONFIG_NET_CLS
struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
bool create);
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 135f5a2dd931..0dec8a23be57 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -10,6 +10,7 @@
#include <linux/dynamic_queue_limits.h>
#include <linux/list.h>
#include <linux/refcount.h>
+#include <linux/workqueue.h>
#include <net/gen_stats.h>
#include <net/rtnetlink.h>
@@ -271,6 +272,7 @@ struct tcf_chain {
struct tcf_block {
struct list_head chain_list;
+ struct work_struct work;
};
static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)