udp: secondary hash on (local port, local address)
Extends udp_table to contain a secondary hash table.
socket anchor for this second hash is free, because UDP
doesnt use skc_bind_node : We define an union to hold
both skc_bind_node & a new hlist_nulls_node udp_portaddr_node
udp_lib_get_port() inserts sockets into second hash chain
(additional cost of one atomic op)
udp_lib_unhash() deletes socket from second hash chain
(additional cost of one atomic op)
Note : No spinlock lockdep annotation is needed, because
lock for the secondary hash chain is always get after
lock for primary hash chain.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 5b4b527..59f0ddf 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -57,6 +57,7 @@
struct inet_sock inet;
#define udp_port_hash inet.sk.__sk_common.skc_u16hashes[0]
#define udp_portaddr_hash inet.sk.__sk_common.skc_u16hashes[1]
+#define udp_portaddr_node inet.sk.__sk_common.skc_portaddr_node
int pending; /* Any pending frames ? */
unsigned int corkflag; /* Cork is required */
__u16 encap_type; /* Is this an Encapsulation socket? */
diff --git a/include/net/sock.h b/include/net/sock.h
index 827366b..3f1a4804 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -105,7 +105,7 @@
/**
* struct sock_common - minimal network layer representation of sockets
* @skc_node: main hash linkage for various protocol lookup tables
- * @skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol
+ * @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
* @skc_refcnt: reference count
* @skc_tx_queue_mapping: tx queue number for this connection
* @skc_hash: hash value used with various protocol lookup tables
@@ -115,6 +115,7 @@
* @skc_reuse: %SO_REUSEADDR setting
* @skc_bound_dev_if: bound device index if != 0
* @skc_bind_node: bind hash linkage for various protocol lookup tables
+ * @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
* @skc_prot: protocol handlers inside a network family
* @skc_net: reference to the network namespace of this socket
*
@@ -140,7 +141,10 @@
volatile unsigned char skc_state;
unsigned char skc_reuse;
int skc_bound_dev_if;
- struct hlist_node skc_bind_node;
+ union {
+ struct hlist_node skc_bind_node;
+ struct hlist_nulls_node skc_portaddr_node;
+ };
struct proto *skc_prot;
#ifdef CONFIG_NET_NS
struct net *skc_net;
diff --git a/include/net/udp.h b/include/net/udp.h
index 9167281..af41850 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -63,10 +63,19 @@
spinlock_t lock;
} __attribute__((aligned(2 * sizeof(long))));
+/**
+ * struct udp_table - UDP table
+ *
+ * @hash: hash table, sockets are hashed on (local port)
+ * @hash2: hash table, sockets are hashed on (local port, local address)
+ * @mask: number of slots in hash tables, minus 1
+ * @log: log2(number of slots in hash table)
+ */
struct udp_table {
struct udp_hslot *hash;
- unsigned int mask;
- unsigned int log;
+ struct udp_hslot *hash2;
+ unsigned int mask;
+ unsigned int log;
};
extern struct udp_table udp_table;
extern void udp_table_init(struct udp_table *, const char *);
@@ -75,6 +84,15 @@
{
return &table->hash[udp_hashfn(net, num, table->mask)];
}
+/*
+ * For secondary hash, net_hash_mix() is performed before calling
+ * udp_hashslot2(), this explains difference with udp_hashslot()
+ */
+static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
+ unsigned int hash)
+{
+ return &table->hash2[hash & table->mask];
+}
/* Note: this must match 'valbool' in sock_setsockopt */
#define UDP_CSUM_NOXMIT 1