Merge branch 'net-sched-prepare-for-more-Qdisc-offloads'

Jakub Kicinski says:

====================
net: sched: prepare for more Qdisc offloads

This series refactors the "switchdev" Qdisc offloads a little.  We have
a few Qdiscs which can be fully offloaded today to the forwarding plane
of switching devices.

First patch adds a helper for handing statistic dumps, the code seems
to be copy pasted between PRIO and RED.  Second patch removes unnecessary
parameter from RED offload function.  Third patch makes the MQ offload
use the dump helper which helps it behave much like PRIO and RED when
it comes to the TCQ_F_OFFLOADED flag.  Patch 4 adds a graft helper,
similar to the dump helper.

Patch 5 is unrelated to offloads, qdisc_graft() code seemed ripe for a
small refactor - no functional changes there.

Last two patches move the qdisc_put() call outside of the sch_tree_lock
section for RED and PRIO.  The child Qdiscs will get removed from the
hierarchy under the lock, but having the put (and potentially destroy)
called outside of the lock helps offload which may choose to sleep,
and it should generally lower the Qdisc change impact.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 4d736427a4cb..a8dd1fc141b6 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -579,6 +579,30 @@ void qdisc_put(struct Qdisc *qdisc);
 void qdisc_put_unlocked(struct Qdisc *qdisc);
 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 			       unsigned int len);
+#ifdef CONFIG_NET_SCHED
+int qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
+			      void *type_data);
+void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
+				struct Qdisc *new, struct Qdisc *old,
+				enum tc_setup_type type, void *type_data,
+				struct netlink_ext_ack *extack);
+#else
+static inline int
+qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
+			  void *type_data)
+{
+	q->flags &= ~TCQ_F_OFFLOADED;
+	return 0;
+}
+
+static inline void
+qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
+			   struct Qdisc *new, struct Qdisc *old,
+			   enum tc_setup_type type, void *type_data,
+			   struct netlink_ext_ack *extack)
+{
+}
+#endif
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 			  const struct Qdisc_ops *ops,
 			  struct netlink_ext_ack *extack);