[RFC PATCH net-next 2/3] flow_offload: restore ability to collect separate stats per action

[Edward Cree]

Introduce a new offload command TC_CLSFLOWER_STATS_BYINDEX, similar to
 the existing TC_CLSFLOWER_STATS but specifying an action_index (the
 tcfa_index of the action), which is called for each stats-having action
 on the rule.  Drivers should implement either, but not both, of these
 commands.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 include/net/pkt_cls.h  |  2 ++
 net/sched/cls_flower.c | 30 ++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index d5e7a1af346f..0e33c52c23a8 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -762,6 +762,7 @@ enum tc_fl_command {
        TC_CLSFLOWER_REPLACE,
        TC_CLSFLOWER_DESTROY,
        TC_CLSFLOWER_STATS,
+       TC_CLSFLOWER_STATS_BYINDEX,
        TC_CLSFLOWER_TMPLT_CREATE,
        TC_CLSFLOWER_TMPLT_DESTROY,
 };
@@ -773,6 +774,7 @@ struct tc_cls_flower_offload {
        struct flow_rule *rule;
        struct flow_stats stats;
        u32 classid;
+       u32 action_index; /* for TC_CLSFLOWER_STATS_BYINDEX */
 };
 
 static inline struct flow_rule *
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index f6685fc53119..be339cd6a86e 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -474,6 +474,10 @@ static void fl_hw_update_stats(struct tcf_proto *tp, 
struct cls_fl_filter *f,
 {
        struct tc_cls_flower_offload cls_flower = {};
        struct tcf_block *block = tp->chain->block;
+#ifdef CONFIG_NET_CLS_ACT
+       struct tc_action *a;
+       int i;
+#endif
 
        if (!rtnl_held)
                rtnl_lock();
@@ -489,6 +493,32 @@ static void fl_hw_update_stats(struct tcf_proto *tp, 
struct cls_fl_filter *f,
                              cls_flower.stats.pkts,
                              cls_flower.stats.lastused);
 
+#ifdef CONFIG_NET_CLS_ACT
+       for (i = 0; i < f->exts.nr_actions; i++) {
+               a = f->exts.actions[i];
+
+               if (!a->ops->stats_update)
+                       continue;
+               memset(&cls_flower, 0, sizeof(cls_flower));
+               tc_cls_common_offload_init(&cls_flower.common, tp, f->flags, 
NULL);
+               cls_flower.command = TC_CLSFLOWER_STATS_BYINDEX;
+               cls_flower.cookie = (unsigned long) f;
+               cls_flower.classid = f->res.classid;
+               cls_flower.action_index = a->tcfa_index;
+
+               tc_setup_cb_call(block, TC_SETUP_CLSFLOWER, &cls_flower, false);
+
+               /* Some ->stats_update() use percpu variables and must thus be
+                * called with preemption disabled.
+                */
+               preempt_disable();
+               a->ops->stats_update(a, cls_flower.stats.bytes,
+                                    cls_flower.stats.pkts,
+                                    cls_flower.stats.lastused, true);
+               preempt_enable();
+       }
+#endif
+
        if (!rtnl_held)
                rtnl_unlock();
 }