net: rcu-ify tcf_proto
rcu'ify tcf_proto this allows calling tc_classify() without holding
any locks. Updaters are protected by RTNL.
This patch prepares the core net_sched infrastracture for running
the classifier/action chains without holding the qdisc lock however
it does nothing to ensure cls_xxx and act_xxx types also work without
locking. Additional patches are required to address the fall out.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 762a04b..a3244a8 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -133,7 +133,7 @@
struct gnet_stats_rate_est64 rate_est;
struct tc_cbq_xstats xstats;
- struct tcf_proto *filter_list;
+ struct tcf_proto __rcu *filter_list;
int refcnt;
int filters;
@@ -221,6 +221,7 @@
struct cbq_class **defmap;
struct cbq_class *cl = NULL;
u32 prio = skb->priority;
+ struct tcf_proto *fl;
struct tcf_result res;
/*
@@ -235,11 +236,12 @@
int result = 0;
defmap = head->defaults;
+ fl = rcu_dereference_bh(head->filter_list);
/*
* Step 2+n. Apply classifier.
*/
- if (!head->filter_list ||
- (result = tc_classify_compat(skb, head->filter_list, &res)) < 0)
+ result = tc_classify_compat(skb, fl, &res);
+ if (!fl || result < 0)
goto fallback;
cl = (void *)res.class;
@@ -1954,7 +1956,8 @@
return 0;
}
-static struct tcf_proto **cbq_find_tcf(struct Qdisc *sch, unsigned long arg)
+static struct tcf_proto __rcu **cbq_find_tcf(struct Qdisc *sch,
+ unsigned long arg)
{
struct cbq_sched_data *q = qdisc_priv(sch);
struct cbq_class *cl = (struct cbq_class *)arg;