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_choke.c b/net/sched/sch_choke.c
index ed30e43..74813e6 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -57,7 +57,7 @@
/* Variables */
struct red_vars vars;
- struct tcf_proto *filter_list;
+ struct tcf_proto __rcu *filter_list;
struct {
u32 prob_drop; /* Early probability drops */
u32 prob_mark; /* Early probability marks */
@@ -193,9 +193,11 @@
{
struct choke_sched_data *q = qdisc_priv(sch);
struct tcf_result res;
+ struct tcf_proto *fl;
int result;
- result = tc_classify(skb, q->filter_list, &res);
+ fl = rcu_dereference_bh(q->filter_list);
+ result = tc_classify(skb, fl, &res);
if (result >= 0) {
#ifdef CONFIG_NET_CLS_ACT
switch (result) {
@@ -249,7 +251,7 @@
return false;
oskb = choke_peek_random(q, pidx);
- if (q->filter_list)
+ if (rcu_access_pointer(q->filter_list))
return choke_get_classid(nskb) == choke_get_classid(oskb);
return choke_match_flow(oskb, nskb);
@@ -257,11 +259,11 @@
static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
+ int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
struct choke_sched_data *q = qdisc_priv(sch);
const struct red_parms *p = &q->parms;
- int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
- if (q->filter_list) {
+ if (rcu_access_pointer(q->filter_list)) {
/* If using external classifiers, get result and record it. */
if (!choke_classify(skb, sch, &ret))
goto other_drop; /* Packet was eaten by filter */
@@ -554,7 +556,8 @@
return 0;
}
-static struct tcf_proto **choke_find_tcf(struct Qdisc *sch, unsigned long cl)
+static struct tcf_proto __rcu **choke_find_tcf(struct Qdisc *sch,
+ unsigned long cl)
{
struct choke_sched_data *q = qdisc_priv(sch);