perf(nfq): make delayed queue count O(1)

Co-authored-by: vemneyy <[email protected]>

nfq/packet_queue.c

@@ -7,6 +7,7 @@
 void rawpacket_queue_init(struct rawpacket_tailhead *q)
 {
 	TAILQ_INIT(q);
+	q->cached_count = 0;
 }
 void rawpacket_free(struct rawpacket *rp)
 {
@@ -17,7 +18,11 @@ struct rawpacket *rawpacket_dequeue(struct rawpacket_tailhead *q)
 {
 	struct rawpacket *rp;
 	rp = TAILQ_FIRST(q);
-	if (rp)	TAILQ_REMOVE(q, rp, next);
+	if (rp)
+	{
+		TAILQ_REMOVE(q, rp, next);
+		q->cached_count--;
+	}
 	return rp;
 }
 void rawpacket_queue_destroy(struct rawpacket_tailhead *q)
@@ -53,16 +58,14 @@ struct rawpacket *rawpacket_queue(struct rawpacket_tailhead *q,const struct sock
 	rp->len_payload=len_payload;
 	
 	TAILQ_INSERT_TAIL(q, rp, next);
+	q->cached_count++;
 	
 	return rp;
 }
 
 unsigned int rawpacket_queue_count(const struct rawpacket_tailhead *q)
 {
-	const struct rawpacket *rp;
-	unsigned int ct=0;
-	TAILQ_FOREACH(rp, q, next) ct++;
-	return ct;
+	return q->cached_count;
 }
 bool rawpacket_queue_empty(const struct rawpacket_tailhead *q)
 {

nfq/packet_queue.h

@@ -15,7 +15,11 @@ struct rawpacket
 	uint8_t *packet;
 	TAILQ_ENTRY(rawpacket) next;
 };
-TAILQ_HEAD(rawpacket_tailhead, rawpacket);
+struct rawpacket_tailhead {
+	struct rawpacket *tqh_first;
+	struct rawpacket **tqh_last;
+	unsigned int cached_count;
+};
 
 void rawpacket_queue_init(struct rawpacket_tailhead *q);
 void rawpacket_queue_destroy(struct rawpacket_tailhead *q);