fq: support filtering a given tin

Add to the FQ API a way to filter a given tin, in order to
remove frames that fulfil certain criteria according to a
filter function.

This will be used by mac80211 to remove frames belonging to
an AP VLAN interface that's being removed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/fq.h b/include/net/fq.h
index 6d8521a..ac944a6 100644
--- a/include/net/fq.h
+++ b/include/net/fq.h
@@ -90,6 +90,13 @@
 			   struct fq_flow *,
 			   struct sk_buff *);
 
+/* Return %true to filter (drop) the frame. */
+typedef bool fq_skb_filter_t(struct fq *,
+			     struct fq_tin *,
+			     struct fq_flow *,
+			     struct sk_buff *,
+			     void *);
+
 typedef struct fq_flow *fq_flow_get_default_t(struct fq *,
 					      struct fq_tin *,
 					      int idx,