net: flow_offload: add flow_block_cb_{priv, incref, decref}()

This patch completes the flow block API to introduce:

* flow_block_cb_priv() to access callback private data.
* flow_block_cb_incref() to bump reference counter on this flow block.
* flow_block_cb_decref() to decrement the reference counter.

These functions are taken from the existing tcf_block_cb_priv(),
tcf_block_cb_incref() and tcf_block_cb_decref().
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_offload.h

@@ -281,6 +281,10 @@ void flow_block_cb_free(struct flow_block_cb *block_cb);
 struct flow_block_cb *flow_block_cb_lookup(struct flow_block_offload *offload,
 					   tc_setup_cb_t *cb, void *cb_ident);
 
+void *flow_block_cb_priv(struct flow_block_cb *block_cb);
+void flow_block_cb_incref(struct flow_block_cb *block_cb);
+unsigned int flow_block_cb_decref(struct flow_block_cb *block_cb);
+
 static inline void flow_block_cb_add(struct flow_block_cb *block_cb,
 				     struct flow_block_offload *offload)
 {

net/core/flow_offload.c

@@ -211,6 +211,24 @@ struct flow_block_cb *flow_block_cb_lookup(struct flow_block_offload *f,
 }
 EXPORT_SYMBOL(flow_block_cb_lookup);
 
+void *flow_block_cb_priv(struct flow_block_cb *block_cb)
+{
+	return block_cb->cb_priv;
+}
+EXPORT_SYMBOL(flow_block_cb_priv);
+
+void flow_block_cb_incref(struct flow_block_cb *block_cb)
+{
+	block_cb->refcnt++;
+}
+EXPORT_SYMBOL(flow_block_cb_incref);
+
+unsigned int flow_block_cb_decref(struct flow_block_cb *block_cb)
+{
+	return --block_cb->refcnt;
+}
+EXPORT_SYMBOL(flow_block_cb_decref);
+
 int flow_block_cb_setup_simple(struct flow_block_offload *f,
 			       struct list_head *driver_block_list,
 			       tc_setup_cb_t *cb, void *cb_ident, void *cb_priv,