udp: add a counter into udp_hslot

Adds a counter in udp_hslot to keep an accurate count
of sockets present in chain.

This will permit to upcoming UDP lookup algo to chose
the shortest chain when secondary hash is added.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/net/udp.h b/include/net/udp.h
index 22aa2e7..9167281 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -50,8 +50,16 @@ struct udp_skb_cb {
 };
 #define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))
 
+/**
+ *	struct udp_hslot - UDP hash slot
+ *
+ *	@head:	head of list of sockets
+ *	@count:	number of sockets in 'head' list
+ *	@lock:	spinlock protecting changes to head/count
+ */
 struct udp_hslot {
 	struct hlist_nulls_head	head;
+	int			count;
 	spinlock_t		lock;
 } __attribute__((aligned(2 * sizeof(long))));