net: sched: add flags to Qdisc class ops struct

Extend Qdisc_class_ops with flags. Create enum to hold possible class ops
flag values. Add first class ops flags value QDISC_CLASS_OPS_DOIT_UNLOCKED
to indicate that class ops functions can be called without taking rtnl
lock.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sch_generic.h

@@ -179,6 +179,7 @@ static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
 }
 
 struct Qdisc_class_ops {
+	unsigned int		flags;
 	/* Child qdisc manipulation */
 	struct netdev_queue *	(*select_queue)(struct Qdisc *, struct tcmsg *);
 	int			(*graft)(struct Qdisc *, unsigned long cl,
@@ -210,6 +211,13 @@ struct Qdisc_class_ops {
 					struct gnet_dump *);
 };
 
+/* Qdisc_class_ops flag values */
+
+/* Implements API that doesn't require rtnl lock */
+enum qdisc_class_ops_flags {
+	QDISC_CLASS_OPS_DOIT_UNLOCKED = 1,
+};
+
 struct Qdisc_ops {
 	struct Qdisc_ops	*next;
 	const struct Qdisc_class_ops	*cl_ops;