[PATCH net-next 11/14] net: sched: mq: add simple offload notification

[Jakub Kicinski]

mq offload is trivial, we just need to let the device know
that the root qdisc is mq.  Alternative approach would be
to export qdisc_lookup() and make drivers check the root
type themselves, but notification via ndo_setup_tc is more
in line with other qdiscs.

Note that mq doesn't hold any stats on it's own, it just
adds up stats of its children.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 include/linux/netdevice.h |  1 +
 include/net/pkt_cls.h     | 10 ++++++++++
 net/sched/sch_mq.c        | 19 +++++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8452f72087ef..29ef76360cc8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -791,6 +791,7 @@ enum tc_setup_type {
        TC_SETUP_QDISC_CBS,
        TC_SETUP_QDISC_RED,
        TC_SETUP_QDISC_PRIO,
+       TC_SETUP_QDISC_MQ,
 };
 
 /* These structures hold the attributes of bpf state that are being passed
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index f3ec43725724..942f839dbca4 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -778,6 +778,16 @@ struct tc_qopt_offload_stats {
        struct gnet_stats_queue *qstats;
 };
 
+enum tc_mq_command {
+       TC_MQ_CREATE,
+       TC_MQ_DESTROY,
+};
+
+struct tc_mq_qopt_offload {
+       enum tc_mq_command command;
+       u32 handle;
+};
+
 enum tc_red_command {
        TC_RED_REPLACE,
        TC_RED_DESTROY,
diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c
index f062a18e9162..6ccf6daa2503 100644
--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c
@@ -16,6 +16,7 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <net/netlink.h>
+#include <net/pkt_cls.h>
 #include <net/pkt_sched.h>
 #include <net/sch_generic.h>
 
@@ -23,12 +24,28 @@ struct mq_sched {
        struct Qdisc            **qdiscs;
 };
 
+static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd)
+{
+       struct net_device *dev = qdisc_dev(sch);
+       struct tc_mq_qopt_offload opt = {
+               .command = cmd,
+               .handle = sch->handle,
+       };
+
+       if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+               return -EOPNOTSUPP;
+
+       return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQ, &opt);
+}
+
 static void mq_destroy(struct Qdisc *sch)
 {
        struct net_device *dev = qdisc_dev(sch);
        struct mq_sched *priv = qdisc_priv(sch);
        unsigned int ntx;
 
+       mq_offload(sch, TC_MQ_DESTROY);
+
        if (!priv->qdiscs)
                return;
        for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
@@ -70,6 +87,8 @@ static int mq_init(struct Qdisc *sch, struct nlattr *opt,
        }
 
        sch->flags |= TCQ_F_MQROOT;
+
+       mq_offload(sch, TC_MQ_CREATE);
        return 0;
 }
 
-- 
2.17.0