[PATCH net-next 1/5] net: sched: Make FIFO Qdisc offloadable

[Ido Schimmel <idosch@idosch.org>]

From: Petr Machata <petrm@mellanox.com>

Invoke ndo_setup_tc() as appropriate to signal init / replacement,
destroying and dumping of pFIFO / bFIFO Qdisc.

A lot of the FIFO logic is used for pFIFO_head_drop as well, but that's a
semantically very different Qdisc that isn't really in the same boat as
pFIFO / bFIFO. Split some of the functions to keep the Qdisc intact.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
---
 include/linux/netdevice.h |  1 +
 include/net/pkt_cls.h     | 15 ++++++
 net/sched/sch_fifo.c      | 97 ++++++++++++++++++++++++++++++++++++---
 3 files changed, 107 insertions(+), 6 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b6fedd54cd8e..654808bfad83 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -853,6 +853,7 @@ enum tc_setup_type {
 	TC_SETUP_FT,
 	TC_SETUP_QDISC_ETS,
 	TC_SETUP_QDISC_TBF,
+	TC_SETUP_QDISC_FIFO,
 };
 
 /* 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 53946b509b51..341a66af8d59 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -881,4 +881,19 @@ struct tc_tbf_qopt_offload {
 	};
 };
 
+enum tc_fifo_command {
+	TC_FIFO_REPLACE,
+	TC_FIFO_DESTROY,
+	TC_FIFO_STATS,
+};
+
+struct tc_fifo_qopt_offload {
+	enum tc_fifo_command command;
+	u32 handle;
+	u32 parent;
+	union {
+		struct tc_qopt_offload_stats stats;
+	};
+};
+
 #endif
diff --git a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c
index 37c8aa75d70c..a579a4131d22 100644
--- a/net/sched/sch_fifo.c
+++ b/net/sched/sch_fifo.c
@@ -12,6 +12,7 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
 
 /* 1 band FIFO pseudo-"scheduler" */
 
@@ -51,8 +52,49 @@ static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	return NET_XMIT_CN;
 }
 
-static int fifo_init(struct Qdisc *sch, struct nlattr *opt,
-		     struct netlink_ext_ack *extack)
+static void fifo_offload_init(struct Qdisc *sch)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	struct tc_fifo_qopt_offload qopt;
+
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+		return;
+
+	qopt.command = TC_FIFO_REPLACE;
+	qopt.handle = sch->handle;
+	qopt.parent = sch->parent;
+	dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_FIFO, &qopt);
+}
+
+static void fifo_offload_destroy(struct Qdisc *sch)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	struct tc_fifo_qopt_offload qopt;
+
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+		return;
+
+	qopt.command = TC_FIFO_DESTROY;
+	qopt.handle = sch->handle;
+	qopt.parent = sch->parent;
+	dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_FIFO, &qopt);
+}
+
+static int fifo_offload_dump(struct Qdisc *sch)
+{
+	struct tc_fifo_qopt_offload qopt;
+
+	qopt.command = TC_FIFO_STATS;
+	qopt.handle = sch->handle;
+	qopt.parent = sch->parent;
+	qopt.stats.bstats = &sch->bstats;
+	qopt.stats.qstats = &sch->qstats;
+
+	return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_FIFO, &qopt);
+}
+
+static int __fifo_init(struct Qdisc *sch, struct nlattr *opt,
+		       struct netlink_ext_ack *extack)
 {
 	bool bypass;
 	bool is_bfifo = sch->ops == &bfifo_qdisc_ops;
@@ -82,10 +124,35 @@ static int fifo_init(struct Qdisc *sch, struct nlattr *opt,
 		sch->flags |= TCQ_F_CAN_BYPASS;
 	else
 		sch->flags &= ~TCQ_F_CAN_BYPASS;
+
 	return 0;
 }
 
-static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
+static int fifo_init(struct Qdisc *sch, struct nlattr *opt,
+		     struct netlink_ext_ack *extack)
+{
+	int err;
+
+	err = __fifo_init(sch, opt, extack);
+	if (err)
+		return err;
+
+	fifo_offload_init(sch);
+	return 0;
+}
+
+static int fifo_hd_init(struct Qdisc *sch, struct nlattr *opt,
+			struct netlink_ext_ack *extack)
+{
+	return __fifo_init(sch, opt, extack);
+}
+
+static void fifo_destroy(struct Qdisc *sch)
+{
+	fifo_offload_destroy(sch);
+}
+
+static int __fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct tc_fifo_qopt opt = { .limit = sch->limit };
 
@@ -97,6 +164,22 @@ static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
 	return -1;
 }
 
+static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	int err;
+
+	err = fifo_offload_dump(sch);
+	if (err)
+		return err;
+
+	return __fifo_dump(sch, skb);
+}
+
+static int fifo_hd_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	return __fifo_dump(sch, skb);
+}
+
 struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
 	.id		=	"pfifo",
 	.priv_size	=	0,
@@ -104,6 +187,7 @@ struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
 	.dequeue	=	qdisc_dequeue_head,
 	.peek		=	qdisc_peek_head,
 	.init		=	fifo_init,
+	.destroy	=	fifo_destroy,
 	.reset		=	qdisc_reset_queue,
 	.change		=	fifo_init,
 	.dump		=	fifo_dump,
@@ -118,6 +202,7 @@ struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
 	.dequeue	=	qdisc_dequeue_head,
 	.peek		=	qdisc_peek_head,
 	.init		=	fifo_init,
+	.destroy	=	fifo_destroy,
 	.reset		=	qdisc_reset_queue,
 	.change		=	fifo_init,
 	.dump		=	fifo_dump,
@@ -131,10 +216,10 @@ struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = {
 	.enqueue	=	pfifo_tail_enqueue,
 	.dequeue	=	qdisc_dequeue_head,
 	.peek		=	qdisc_peek_head,
-	.init		=	fifo_init,
+	.init		=	fifo_hd_init,
 	.reset		=	qdisc_reset_queue,
-	.change		=	fifo_init,
-	.dump		=	fifo_dump,
+	.change		=	fifo_hd_init,
+	.dump		=	fifo_hd_dump,
 	.owner		=	THIS_MODULE,
 };
 
-- 
2.24.1