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_sfq.c b/net/sched/sch_sfq.c
index 211db90..80c36bd 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -125,7 +125,7 @@
u8 cur_depth; /* depth of longest slot */
u8 flags;
unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
- struct tcf_proto *filter_list;
+ struct tcf_proto __rcu *filter_list;
sfq_index *ht; /* Hash table ('divisor' slots) */
struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
@@ -187,6 +187,7 @@
{
struct sfq_sched_data *q = qdisc_priv(sch);
struct tcf_result res;
+ struct tcf_proto *fl;
int result;
if (TC_H_MAJ(skb->priority) == sch->handle &&
@@ -194,13 +195,14 @@
TC_H_MIN(skb->priority) <= q->divisor)
return TC_H_MIN(skb->priority);
- if (!q->filter_list) {
+ fl = rcu_dereference_bh(q->filter_list);
+ if (!fl) {
skb_flow_dissect(skb, &sfq_skb_cb(skb)->keys);
return sfq_hash(q, skb) + 1;
}
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
- result = tc_classify(skb, q->filter_list, &res);
+ result = tc_classify(skb, fl, &res);
if (result >= 0) {
#ifdef CONFIG_NET_CLS_ACT
switch (result) {
@@ -836,7 +838,8 @@
{
}
-static struct tcf_proto **sfq_find_tcf(struct Qdisc *sch, unsigned long cl)
+static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch,
+ unsigned long cl)
{
struct sfq_sched_data *q = qdisc_priv(sch);