[patch net-next 09/10] net: sch: prio: Add offload ability for grafting a child

[Jiri Pirko]

From: Nogah Frankel <nog...@mellanox.com>

Offload sch_prio graft command for capable drivers.
Warn in case of a failure, unless the graft was done as part of a destroy
operation (the new qdisc is a noop) or if all the qdiscs (the parent, the
old child, and the new one) are not offloaded.

Signed-off-by: Nogah Frankel <nog...@mellanox.com>
Reviewed-by: Yuval Mintz <yuv...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 include/net/pkt_cls.h |  8 ++++++++
 net/sched/sch_prio.c  | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 87406252f0a3..e828d31be5da 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -806,6 +806,7 @@ enum tc_prio_command {
        TC_PRIO_REPLACE,
        TC_PRIO_DESTROY,
        TC_PRIO_STATS,
+       TC_PRIO_GRAFT,
 };
 
 struct tc_prio_qopt_offload_params {
@@ -818,6 +819,11 @@ struct tc_prio_qopt_offload_params {
        struct gnet_stats_queue *qstats;
 };
 
+struct tc_prio_qopt_offload_graft_params {
+       u8 band;
+       u32 child_handle;
+};
+
 struct tc_prio_qopt_offload {
        enum tc_prio_command command;
        u32 handle;
@@ -825,6 +831,8 @@ struct tc_prio_qopt_offload {
        union {
                struct tc_prio_qopt_offload_params replace_params;
                struct tc_qopt_offload_stats stats;
+               struct tc_prio_qopt_offload_graft_params graft_params;
        };
 };
+
 #endif
diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index ba2d6d17d95a..222e53d3d27a 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -308,12 +308,44 @@ static int prio_graft(struct Qdisc *sch, unsigned long 
arg, struct Qdisc *new,
                      struct Qdisc **old, struct netlink_ext_ack *extack)
 {
        struct prio_sched_data *q = qdisc_priv(sch);
+       struct tc_prio_qopt_offload graft_offload;
+       struct net_device *dev = qdisc_dev(sch);
        unsigned long band = arg - 1;
+       bool any_qdisc_is_offloaded;
+       int err;
 
        if (new == NULL)
                new = &noop_qdisc;
 
        *old = qdisc_replace(sch, new, &q->queues[band]);
+
+       if (!tc_can_offload(dev))
+               return 0;
+
+       graft_offload.handle = sch->handle;
+       graft_offload.parent = sch->parent;
+       graft_offload.graft_params.band = band;
+       graft_offload.graft_params.child_handle = new->handle;
+       graft_offload.command = TC_PRIO_GRAFT;
+
+       err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO,
+                                           &graft_offload);
+
+       /* Don't report error if the graft is part of destroy operation. */
+       if (err && new != &noop_qdisc) {
+               /* Don't report error if the parent, the old child and the new
+                * one are not offloaded.
+                */
+               any_qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
+               any_qdisc_is_offloaded |= new->flags & TCQ_F_OFFLOADED;
+               if (*old)
+                       any_qdisc_is_offloaded |= (*old)->flags &
+                                                  TCQ_F_OFFLOADED;
+
+               if (any_qdisc_is_offloaded)
+                       NL_SET_ERR_MSG(extack, "Offloading graft operation 
failed.");
+       }
+
        return 0;
 }
 
-- 
2.14.3