tipc: convert tipc reference table to use generic rhashtable

As tipc reference table is statically allocated, its memory size
requested on stack initialization stage is quite big even if the
maximum port number is just restricted to 8191 currently, however,
the number already becomes insufficient in practice. But if the
maximum ports is allowed to its theory value - 2^32, its consumed
memory size will reach a ridiculously unacceptable value. Apart from
this, heavy tipc users spend a considerable amount of time in
tipc_sk_get() due to the read-lock on ref_table_lock.

If tipc reference table is converted with generic rhashtable, above
mentioned both disadvantages would be resolved respectively: making
use of the new resizable hash table can avoid locking on the lookup;
smaller memory size is required at initial stage, for example, 256
hash bucket slots are requested at the beginning phase instead of
allocating the entire 8191 slots in old mode. The hash table will
grow if entries exceeds 75% of table size up to a total table size
of 1M, and it will automatically shrink if usage falls below 30%,
but the minimum table size is allowed down to 256.

Also converts ref_table_lock to a separate mutex to protect hash table
mutations on write side. Lastly defers the release of the socket
reference using call_rcu() to allow using an RCU read-side protected
call to rhashtable_lookup().

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Erik Hugne <erik.hugne@ericsson.com>
Cc: Thomas Graf <tgraf@suug.ch>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 171 insertions, 309 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 4731cad99d1c..701f31bbbbfb 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -34,22 +34,25 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <linux/rhashtable.h>
+#include <linux/jhash.h>
 #include "core.h"
 #include "name_table.h"
 #include "node.h"
 #include "link.h"
-#include <linux/export.h>
 #include "config.h"
 #include "socket.h"
 
-#define SS_LISTENING	-1	/* socket is listening */
-#define SS_READY	-2	/* socket is connectionless */
+#define SS_LISTENING		-1	/* socket is listening */
+#define SS_READY		-2	/* socket is connectionless */
 
-#define CONN_TIMEOUT_DEFAULT  8000	/* default connect timeout = 8s */
-#define CONN_PROBING_INTERVAL 3600000	/* [ms] => 1 h */
-#define TIPC_FWD_MSG	      1
-#define TIPC_CONN_OK          0
-#define TIPC_CONN_PROBING     1
+#define CONN_TIMEOUT_DEFAULT	8000	/* default connect timeout = 8s */
+#define CONN_PROBING_INTERVAL	3600000	/* [ms] => 1 h */
+#define TIPC_FWD_MSG		1
+#define TIPC_CONN_OK		0
+#define TIPC_CONN_PROBING	1
+#define TIPC_MAX_PORT		0xffffffff
+#define TIPC_MIN_PORT		1
 
 /**
  * struct tipc_sock - TIPC socket structure
@@ -59,7 +62,7 @@
  * @conn_instance: TIPC instance used when connection was established
  * @published: non-zero if port has one or more associated names
  * @max_pkt: maximum packet size "hint" used when building messages sent by port
- * @ref: unique reference to port in TIPC object registry
+ * @portid: unique port identity in TIPC socket hash table
  * @phdr: preformatted message header used when sending messages
  * @port_list: adjacent ports in TIPC's global list of ports
  * @publications: list of publications for port
@@ -74,6 +77,8 @@
  * @link_cong: non-zero if owner must sleep because of link congestion
  * @sent_unacked: # messages sent by socket, and not yet acked by peer
  * @rcv_unacked: # messages read by user, but not yet acked back to peer
+ * @node: hash table node
+ * @rcu: rcu struct for tipc_sock
  */
 struct tipc_sock {
 	struct sock sk;
@@ -82,7 +87,7 @@ struct tipc_sock {
 	u32 conn_instance;
 	int published;
 	u32 max_pkt;
-	u32 ref;
+	u32 portid;
 	struct tipc_msg phdr;
 	struct list_head sock_list;
 	struct list_head publications;
@@ -95,6 +100,8 @@ struct tipc_sock {
 	bool link_cong;
 	uint sent_unacked;
 	uint rcv_unacked;
+	struct rhash_head node;
+	struct rcu_head rcu;
 };
 
 static int tipc_backlog_rcv(struct sock *sk, struct sk_buff *skb);
@@ -103,16 +110,14 @@ static void tipc_write_space(struct sock *sk);
 static int tipc_release(struct socket *sock);
 static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags);
 static int tipc_wait_for_sndmsg(struct socket *sock, long *timeo_p);
-static void tipc_sk_timeout(unsigned long ref);
+static void tipc_sk_timeout(unsigned long portid);
 static int tipc_sk_publish(struct tipc_sock *tsk, uint scope,
 			   struct tipc_name_seq const *seq);
 static int tipc_sk_withdraw(struct tipc_sock *tsk, uint scope,
 			    struct tipc_name_seq const *seq);
-static u32 tipc_sk_ref_acquire(struct tipc_sock *tsk);
-static void tipc_sk_ref_discard(u32 ref);
-static struct tipc_sock *tipc_sk_get(u32 ref);
-static struct tipc_sock *tipc_sk_get_next(u32 *ref);
-static void tipc_sk_put(struct tipc_sock *tsk);
+static struct tipc_sock *tipc_sk_lookup(u32 portid);
+static int tipc_sk_insert(struct tipc_sock *tsk);
+static void tipc_sk_remove(struct tipc_sock *tsk);
 
 static const struct proto_ops packet_ops;
 static const struct proto_ops stream_ops;
@@ -174,6 +179,9 @@ static const struct nla_policy tipc_nl_sock_policy[TIPC_NLA_SOCK_MAX + 1] = {
  *   - port reference
  */
 
+/* Protects tipc socket hash table mutations */
+static struct rhashtable tipc_sk_rht;
+
 static u32 tsk_peer_node(struct tipc_sock *tsk)
 {
 	return msg_destnode(&tsk->phdr);
@@ -305,7 +313,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
 	struct sock *sk;
 	struct tipc_sock *tsk;
 	struct tipc_msg *msg;
-	u32 ref;
 
 	/* Validate arguments */
 	if (unlikely(protocol != 0))
@@ -339,24 +346,22 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
 		return -ENOMEM;
 
 	tsk = tipc_sk(sk);
-	ref = tipc_sk_ref_acquire(tsk);
-	if (!ref) {
-		pr_warn("Socket create failed; reference table exhausted\n");
-		return -ENOMEM;
-	}
 	tsk->max_pkt = MAX_PKT_DEFAULT;
-	tsk->ref = ref;
 	INIT_LIST_HEAD(&tsk->publications);
 	msg = &tsk->phdr;
 	tipc_msg_init(msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
 		      NAMED_H_SIZE, 0);
-	msg_set_origport(msg, ref);
 
 	/* Finish initializing socket data structures */
 	sock->ops = ops;
 	sock->state = state;
 	sock_init_data(sock, sk);
-	k_init_timer(&tsk->timer, (Handler)tipc_sk_timeout, ref);
+	if (tipc_sk_insert(tsk)) {
+		pr_warn("Socket create failed; port numbrer exhausted\n");
+		return -EINVAL;
+	}
+	msg_set_origport(msg, tsk->portid);
+	k_init_timer(&tsk->timer, (Handler)tipc_sk_timeout, tsk->portid);
 	sk->sk_backlog_rcv = tipc_backlog_rcv;
 	sk->sk_rcvbuf = sysctl_tipc_rmem[1];
 	sk->sk_data_ready = tipc_data_ready;
@@ -442,6 +447,13 @@ int tipc_sock_accept_local(struct socket *sock, struct socket **newsock,
 	return ret;
 }
 
+static void tipc_sk_callback(struct rcu_head *head)
+{
+	struct tipc_sock *tsk = container_of(head, struct tipc_sock, rcu);
+
+	sock_put(&tsk->sk);
+}
+
 /**
  * tipc_release - destroy a TIPC socket
  * @sock: socket to destroy
@@ -491,7 +503,7 @@ static int tipc_release(struct socket *sock)
 			    (sock->state == SS_CONNECTED)) {
 				sock->state = SS_DISCONNECTING;
 				tsk->connected = 0;
-				tipc_node_remove_conn(dnode, tsk->ref);
+				tipc_node_remove_conn(dnode, tsk->portid);
 			}
 			if (tipc_msg_reverse(skb, &dnode, TIPC_ERR_NO_PORT))
 				tipc_link_xmit_skb(skb, dnode, 0);
@@ -499,16 +511,16 @@ static int tipc_release(struct socket *sock)
 	}
 
 	tipc_sk_withdraw(tsk, 0, NULL);
-	tipc_sk_ref_discard(tsk->ref);
 	k_cancel_timer(&tsk->timer);
+	tipc_sk_remove(tsk);
 	if (tsk->connected) {
 		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
 				      SHORT_H_SIZE, 0, dnode, tipc_own_addr,
 				      tsk_peer_port(tsk),
-				      tsk->ref, TIPC_ERR_NO_PORT);
+				      tsk->portid, TIPC_ERR_NO_PORT);
 		if (skb)
-			tipc_link_xmit_skb(skb, dnode, tsk->ref);
-		tipc_node_remove_conn(dnode, tsk->ref);
+			tipc_link_xmit_skb(skb, dnode, tsk->portid);
+		tipc_node_remove_conn(dnode, tsk->portid);
 	}
 	k_term_timer(&tsk->timer);
 
@@ -518,7 +530,8 @@ static int tipc_release(struct socket *sock)
 	/* Reject any messages that accumulated in backlog queue */
 	sock->state = SS_DISCONNECTING;
 	release_sock(sk);
-	sock_put(sk);
+
+	call_rcu(&tsk->rcu, tipc_sk_callback);
 	sock->sk = NULL;
 
 	return 0;
@@ -611,7 +624,7 @@ static int tipc_getname(struct socket *sock, struct sockaddr *uaddr,
 		addr->addr.id.ref = tsk_peer_port(tsk);
 		addr->addr.id.node = tsk_peer_node(tsk);
 	} else {
-		addr->addr.id.ref = tsk->ref;
+		addr->addr.id.ref = tsk->portid;
 		addr->addr.id.node = tipc_own_addr;
 	}
 
@@ -946,7 +959,7 @@ static int tipc_sendmsg(struct kiocb *iocb, struct socket *sock,
 	}
 
 new_mtu:
-	mtu = tipc_node_get_mtu(dnode, tsk->ref);
+	mtu = tipc_node_get_mtu(dnode, tsk->portid);
 	__skb_queue_head_init(&head);
 	rc = tipc_msg_build(mhdr, m, 0, dsz, mtu, &head);
 	if (rc < 0)
@@ -955,7 +968,7 @@ new_mtu:
 	do {
 		skb = skb_peek(&head);
 		TIPC_SKB_CB(skb)->wakeup_pending = tsk->link_cong;
-		rc = tipc_link_xmit(&head, dnode, tsk->ref);
+		rc = tipc_link_xmit(&head, dnode, tsk->portid);
 		if (likely(rc >= 0)) {
 			if (sock->state != SS_READY)
 				sock->state = SS_CONNECTING;
@@ -1028,7 +1041,7 @@ static int tipc_send_stream(struct kiocb *iocb, struct socket *sock,
 	struct tipc_msg *mhdr = &tsk->phdr;
 	struct sk_buff_head head;
 	DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);
-	u32 ref = tsk->ref;
+	u32 portid = tsk->portid;
 	int rc = -EINVAL;
 	long timeo;
 	u32 dnode;
@@ -1067,7 +1080,7 @@ next:
 		goto exit;
 	do {
 		if (likely(!tsk_conn_cong(tsk))) {
-			rc = tipc_link_xmit(&head, dnode, ref);
+			rc = tipc_link_xmit(&head, dnode, portid);
 			if (likely(!rc)) {
 				tsk->sent_unacked++;
 				sent += send;
@@ -1076,7 +1089,7 @@ next:
 				goto next;
 			}
 			if (rc == -EMSGSIZE) {
-				tsk->max_pkt = tipc_node_get_mtu(dnode, ref);
+				tsk->max_pkt = tipc_node_get_mtu(dnode, portid);
 				goto next;
 			}
 			if (rc != -ELINKCONG)
@@ -1130,8 +1143,8 @@ static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,
 	tsk->probing_state = TIPC_CONN_OK;
 	tsk->connected = 1;
 	k_start_timer(&tsk->timer, tsk->probing_interval);
-	tipc_node_add_conn(peer_node, tsk->ref, peer_port);
-	tsk->max_pkt = tipc_node_get_mtu(peer_node, tsk->ref);
+	tipc_node_add_conn(peer_node, tsk->portid, peer_port);
+	tsk->max_pkt = tipc_node_get_mtu(peer_node, tsk->portid);
 }
 
 /**
@@ -1238,7 +1251,7 @@ static void tipc_sk_send_ack(struct tipc_sock *tsk, uint ack)
 	if (!tsk->connected)
 		return;
 	skb = tipc_msg_create(CONN_MANAGER, CONN_ACK, INT_H_SIZE, 0, dnode,
-			      tipc_own_addr, peer_port, tsk->ref, TIPC_OK);
+			      tipc_own_addr, peer_port, tsk->portid, TIPC_OK);
 	if (!skb)
 		return;
 	msg = buf_msg(skb);
@@ -1552,7 +1565,7 @@ static int filter_connect(struct tipc_sock *tsk, struct sk_buff **buf)
 				tsk->connected = 0;
 				/* let timer expire on it's own */
 				tipc_node_remove_conn(tsk_peer_node(tsk),
-						      tsk->ref);
+						      tsk->portid);
 			}
 			retval = TIPC_OK;
 		}
@@ -1743,7 +1756,7 @@ int tipc_sk_rcv(struct sk_buff *skb)
 	u32 dnode;
 
 	/* Validate destination and message */
-	tsk = tipc_sk_get(dport);
+	tsk = tipc_sk_lookup(dport);
 	if (unlikely(!tsk)) {
 		rc = tipc_msg_eval(skb, &dnode);
 		goto exit;
@@ -1763,7 +1776,7 @@ int tipc_sk_rcv(struct sk_buff *skb)
 			rc = -TIPC_ERR_OVERLOAD;
 	}
 	spin_unlock_bh(&sk->sk_lock.slock);
-	tipc_sk_put(tsk);
+	sock_put(sk);
 	if (likely(!rc))
 		return 0;
 exit:
@@ -2050,20 +2063,20 @@ restart:
 				goto restart;
 			}
 			if (tipc_msg_reverse(skb, &dnode, TIPC_CONN_SHUTDOWN))
-				tipc_link_xmit_skb(skb, dnode, tsk->ref);
-			tipc_node_remove_conn(dnode, tsk->ref);
+				tipc_link_xmit_skb(skb, dnode, tsk->portid);
+			tipc_node_remove_conn(dnode, tsk->portid);
 		} else {
 			dnode = tsk_peer_node(tsk);
 			skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE,
 					      TIPC_CONN_MSG, SHORT_H_SIZE,
 					      0, dnode, tipc_own_addr,
 					      tsk_peer_port(tsk),
-					      tsk->ref, TIPC_CONN_SHUTDOWN);
-			tipc_link_xmit_skb(skb, dnode, tsk->ref);
+					      tsk->portid, TIPC_CONN_SHUTDOWN);
+			tipc_link_xmit_skb(skb, dnode, tsk->portid);
 		}
 		tsk->connected = 0;
 		sock->state = SS_DISCONNECTING;
-		tipc_node_remove_conn(dnode, tsk->ref);
+		tipc_node_remove_conn(dnode, tsk->portid);
 		/* fall through */
 
 	case SS_DISCONNECTING:
@@ -2084,14 +2097,14 @@ restart:
 	return res;
 }
 
-static void tipc_sk_timeout(unsigned long ref)
+static void tipc_sk_timeout(unsigned long portid)
 {
 	struct tipc_sock *tsk;
 	struct sock *sk;
 	struct sk_buff *skb = NULL;
 	u32 peer_port, peer_node;
 
-	tsk = tipc_sk_get(ref);
+	tsk = tipc_sk_lookup(portid);
 	if (!tsk)
 		return;
 
@@ -2108,20 +2121,20 @@ static void tipc_sk_timeout(unsigned long ref)
 		/* Previous probe not answered -> self abort */
 		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
 				      SHORT_H_SIZE, 0, tipc_own_addr,
-				      peer_node, ref, peer_port,
+				      peer_node, portid, peer_port,
 				      TIPC_ERR_NO_PORT);
 	} else {
 		skb = tipc_msg_create(CONN_MANAGER, CONN_PROBE, INT_H_SIZE,
 				      0, peer_node, tipc_own_addr,
-				      peer_port, ref, TIPC_OK);
+				      peer_port, portid, TIPC_OK);
 		tsk->probing_state = TIPC_CONN_PROBING;
 		k_start_timer(&tsk->timer, tsk->probing_interval);
 	}
 	bh_unlock_sock(sk);
 	if (skb)
-		tipc_link_xmit_skb(skb, peer_node, ref);
+		tipc_link_xmit_skb(skb, peer_node, portid);
 exit:
-	tipc_sk_put(tsk);
+	sock_put(sk);
 }
 
 static int tipc_sk_publish(struct tipc_sock *tsk, uint scope,
@@ -2132,12 +2145,12 @@ static int tipc_sk_publish(struct tipc_sock *tsk, uint scope,
 
 	if (tsk->connected)
 		return -EINVAL;
-	key = tsk->ref + tsk->pub_count + 1;
-	if (key == tsk->ref)
+	key = tsk->portid + tsk->pub_count + 1;
+	if (key == tsk->portid)
 		return -EADDRINUSE;
 
 	publ = tipc_nametbl_publish(seq->type, seq->lower, seq->upper,
-				    scope, tsk->ref, key);
+				    scope, tsk->portid, key);
 	if (unlikely(!publ))
 		return -EINVAL;
 
@@ -2188,9 +2201,9 @@ static int tipc_sk_show(struct tipc_sock *tsk, char *buf,
 		ret = tipc_snprintf(buf, len, "<%u.%u.%u:%u>:",
 				    tipc_zone(tipc_own_addr),
 				    tipc_cluster(tipc_own_addr),
-				    tipc_node(tipc_own_addr), tsk->ref);
+				    tipc_node(tipc_own_addr), tsk->portid);
 	else
-		ret = tipc_snprintf(buf, len, "%-10u:", tsk->ref);
+		ret = tipc_snprintf(buf, len, "%-10u:", tsk->portid);
 
 	if (tsk->connected) {
 		u32 dport = tsk_peer_port(tsk);
@@ -2224,13 +2237,15 @@ static int tipc_sk_show(struct tipc_sock *tsk, char *buf,
 
 struct sk_buff *tipc_sk_socks_show(void)
 {
+	const struct bucket_table *tbl;
+	struct rhash_head *pos;
 	struct sk_buff *buf;
 	struct tlv_desc *rep_tlv;
 	char *pb;
 	int pb_len;
 	struct tipc_sock *tsk;
 	int str_len = 0;
-	u32 ref = 0;
+	int i;
 
 	buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
 	if (!buf)
@@ -2239,14 +2254,18 @@ struct sk_buff *tipc_sk_socks_show(void)
 	pb = TLV_DATA(rep_tlv);
 	pb_len = ULTRA_STRING_MAX_LEN;
 
-	tsk = tipc_sk_get_next(&ref);
-	for (; tsk; tsk = tipc_sk_get_next(&ref)) {
-		lock_sock(&tsk->sk);
-		str_len += tipc_sk_show(tsk, pb + str_len,
-					pb_len - str_len, 0);
-		release_sock(&tsk->sk);
-		tipc_sk_put(tsk);
+	rcu_read_lock();
+	tbl = rht_dereference_rcu((&tipc_sk_rht)->tbl, &tipc_sk_rht);
+	for (i = 0; i < tbl->size; i++) {
+		rht_for_each_entry_rcu(tsk, pos, tbl, i, node) {
+			spin_lock_bh(&tsk->sk.sk_lock.slock);
+			str_len += tipc_sk_show(tsk, pb + str_len,
+						pb_len - str_len, 0);
+			spin_unlock_bh(&tsk->sk.sk_lock.slock);
+		}
 	}
+	rcu_read_unlock();
+
 	str_len += 1;	/* for "\0" */
 	skb_put(buf, TLV_SPACE(str_len));
 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
@@ -2259,255 +2278,91 @@ struct sk_buff *tipc_sk_socks_show(void)
  */
 void tipc_sk_reinit(void)
 {
+	const struct bucket_table *tbl;
+	struct rhash_head *pos;
+	struct tipc_sock *tsk;
 	struct tipc_msg *msg;
-	u32 ref = 0;
-	struct tipc_sock *tsk = tipc_sk_get_next(&ref);
+	int i;
 
-	for (; tsk; tsk = tipc_sk_get_next(&ref)) {
-		lock_sock(&tsk->sk);
-		msg = &tsk->phdr;
-		msg_set_prevnode(msg, tipc_own_addr);
-		msg_set_orignode(msg, tipc_own_addr);
-		release_sock(&tsk->sk);
-		tipc_sk_put(tsk);
+	rcu_read_lock();
+	tbl = rht_dereference_rcu((&tipc_sk_rht)->tbl, &tipc_sk_rht);
+	for (i = 0; i < tbl->size; i++) {
+		rht_for_each_entry_rcu(tsk, pos, tbl, i, node) {
+			spin_lock_bh(&tsk->sk.sk_lock.slock);
+			msg = &tsk->phdr;
+			msg_set_prevnode(msg, tipc_own_addr);
+			msg_set_orignode(msg, tipc_own_addr);
+			spin_unlock_bh(&tsk->sk.sk_lock.slock);
+		}
 	}
+	rcu_read_unlock();
 }
 
-/**
- * struct reference - TIPC socket reference entry
- * @tsk: pointer to socket associated with reference entry
- * @ref: reference value for socket (combines instance & array index info)
- */
-struct reference {
-	struct tipc_sock *tsk;
-	u32 ref;
-};
-
-/**
- * struct tipc_ref_table - table of TIPC socket reference entries
- * @entries: pointer to array of reference entries
- * @capacity: array index of first unusable entry
- * @init_point: array index of first uninitialized entry
- * @first_free: array index of first unused socket reference entry
- * @last_free: array index of last unused socket reference entry
- * @index_mask: bitmask for array index portion of reference values
- * @start_mask: initial value for instance value portion of reference values
- */
-struct ref_table {
-	struct reference *entries;
-	u32 capacity;
-	u32 init_point;
-	u32 first_free;
-	u32 last_free;
-	u32 index_mask;
-	u32 start_mask;
-};
-
-/* Socket reference table consists of 2**N entries.
- *
- * State	Socket ptr	Reference
- * -----        ----------      ---------
- * In use        non-NULL       XXXX|own index
- *				(XXXX changes each time entry is acquired)
- * Free            NULL         YYYY|next free index
- *				(YYYY is one more than last used XXXX)
- * Uninitialized   NULL         0
- *
- * Entry 0 is not used; this allows index 0 to denote the end of the free list.
- *
- * Note that a reference value of 0 does not necessarily indicate that an
- * entry is uninitialized, since the last entry in the free list could also
- * have a reference value of 0 (although this is unlikely).
- */
-
-static struct ref_table tipc_ref_table;
-
-static DEFINE_RWLOCK(ref_table_lock);
-
-/**
- * tipc_ref_table_init - create reference table for sockets
- */
-int tipc_sk_ref_table_init(u32 req_sz, u32 start)
+static struct tipc_sock *tipc_sk_lookup(u32 portid)
 {
-	struct reference *table;
-	u32 actual_sz;
-
-	/* account for unused entry, then round up size to a power of 2 */
-
-	req_sz++;
-	for (actual_sz = 16; actual_sz < req_sz; actual_sz <<= 1) {
-		/* do nothing */
-	};
-
-	/* allocate table & mark all entries as uninitialized */
-	table = vzalloc(actual_sz * sizeof(struct reference));
-	if (table == NULL)
-		return -ENOMEM;
-
-	tipc_ref_table.entries = table;
-	tipc_ref_table.capacity = req_sz;
-	tipc_ref_table.init_point = 1;
-	tipc_ref_table.first_free = 0;
-	tipc_ref_table.last_free = 0;
-	tipc_ref_table.index_mask = actual_sz - 1;
-	tipc_ref_table.start_mask = start & ~tipc_ref_table.index_mask;
+	struct tipc_sock *tsk;
 
-	return 0;
-}
+	rcu_read_lock();
+	tsk = rhashtable_lookup(&tipc_sk_rht, &portid);
+	if (tsk)
+		sock_hold(&tsk->sk);
+	rcu_read_unlock();
 
-/**
- * tipc_ref_table_stop - destroy reference table for sockets
- */
-void tipc_sk_ref_table_stop(void)
-{
-	if (!tipc_ref_table.entries)
-		return;
-	vfree(tipc_ref_table.entries);
-	tipc_ref_table.entries = NULL;
+	return tsk;
 }
 
-/* tipc_ref_acquire - create reference to a socket
- *
- * Register an socket pointer in the reference table.
- * Returns a unique reference value that is used from then on to retrieve the
- * socket pointer, or to determine if the socket has been deregistered.
- */
-u32 tipc_sk_ref_acquire(struct tipc_sock *tsk)
+static int tipc_sk_insert(struct tipc_sock *tsk)
 {
-	u32 index;
-	u32 index_mask;
-	u32 next_plus_upper;
-	u32 ref = 0;
-	struct reference *entry;
-
-	if (unlikely(!tsk)) {
-		pr_err("Attempt to acquire ref. to non-existent obj\n");
-		return 0;
-	}
-	if (unlikely(!tipc_ref_table.entries)) {
-		pr_err("Ref. table not found in acquisition attempt\n");
-		return 0;
-	}
-
-	/* Take a free entry, if available; otherwise initialize a new one */
-	write_lock_bh(&ref_table_lock);
-	index = tipc_ref_table.first_free;
-	entry = &tipc_ref_table.entries[index];
+	u32 remaining = (TIPC_MAX_PORT - TIPC_MIN_PORT) + 1;
+	u32 portid = prandom_u32() % remaining + TIPC_MIN_PORT;
 
-	if (likely(index)) {
-		index = tipc_ref_table.first_free;
-		entry = &tipc_ref_table.entries[index];
-		index_mask = tipc_ref_table.index_mask;
-		next_plus_upper = entry->ref;
-		tipc_ref_table.first_free = next_plus_upper & index_mask;
-		ref = (next_plus_upper & ~index_mask) + index;
-		entry->tsk = tsk;
-	} else if (tipc_ref_table.init_point < tipc_ref_table.capacity) {
-		index = tipc_ref_table.init_point++;
-		entry = &tipc_ref_table.entries[index];
-		ref = tipc_ref_table.start_mask + index;
+	while (remaining--) {
+		portid++;
+		if ((portid < TIPC_MIN_PORT) || (portid > TIPC_MAX_PORT))
+			portid = TIPC_MIN_PORT;
+		tsk->portid = portid;
+		sock_hold(&tsk->sk);
+		if (rhashtable_lookup_insert(&tipc_sk_rht, &tsk->node))
+			return 0;
+		sock_put(&tsk->sk);
 	}
 
-	if (ref) {
-		entry->ref = ref;
-		entry->tsk = tsk;
-	}
-	write_unlock_bh(&ref_table_lock);
-	return ref;
+	return -1;
 }
 
-/* tipc_sk_ref_discard - invalidate reference to an socket
- *
- * Disallow future references to an socket and free up the entry for re-use.
- */
-void tipc_sk_ref_discard(u32 ref)
+static void tipc_sk_remove(struct tipc_sock *tsk)
 {
-	struct reference *entry;
-	u32 index;
-	u32 index_mask;
-
-	if (unlikely(!tipc_ref_table.entries)) {
-		pr_err("Ref. table not found during discard attempt\n");
-		return;
-	}
-
-	index_mask = tipc_ref_table.index_mask;
-	index = ref & index_mask;
-	entry = &tipc_ref_table.entries[index];
-
-	write_lock_bh(&ref_table_lock);
+	struct sock *sk = &tsk->sk;
 
-	if (unlikely(!entry->tsk)) {
-		pr_err("Attempt to discard ref. to non-existent socket\n");
-		goto exit;
-	}
-	if (unlikely(entry->ref != ref)) {
-		pr_err("Attempt to discard non-existent reference\n");
-		goto exit;
+	if (rhashtable_remove(&tipc_sk_rht, &tsk->node)) {
+		WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
+		__sock_put(sk);
 	}
-
-	/* Mark entry as unused; increment instance part of entry's
-	 *   reference to invalidate any subsequent references
-	 */
-
-	entry->tsk = NULL;
-	entry->ref = (ref & ~index_mask) + (index_mask + 1);
-
-	/* Append entry to free entry list */
-	if (unlikely(tipc_ref_table.first_free == 0))
-		tipc_ref_table.first_free = index;
-	else
-		tipc_ref_table.entries[tipc_ref_table.last_free].ref |= index;
-	tipc_ref_table.last_free = index;
-exit:
-	write_unlock_bh(&ref_table_lock);
 }
 
-/* tipc_sk_get - find referenced socket and return pointer to it
- */
-struct tipc_sock *tipc_sk_get(u32 ref)
+int tipc_sk_rht_init(void)
 {
-	struct reference *entry;
-	struct tipc_sock *tsk;
+	struct rhashtable_params rht_params = {
+		.nelem_hint = 192,
+		.head_offset = offsetof(struct tipc_sock, node),
+		.key_offset = offsetof(struct tipc_sock, portid),
+		.key_len = sizeof(u32), /* portid */
+		.hashfn = jhash,
+		.max_shift = 20, /* 1M */
+		.min_shift = 8,  /* 256 */
+		.grow_decision = rht_grow_above_75,
+		.shrink_decision = rht_shrink_below_30,
+	};
 
-	if (unlikely(!tipc_ref_table.entries))
-		return NULL;
-	read_lock_bh(&ref_table_lock);
-	entry = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
-	tsk = entry->tsk;
-	if (likely(tsk && (entry->ref == ref)))
-		sock_hold(&tsk->sk);
-	else
-		tsk = NULL;
-	read_unlock_bh(&ref_table_lock);
-	return tsk;
+	return rhashtable_init(&tipc_sk_rht, &rht_params);
 }
 
-/* tipc_sk_get_next - lock & return next socket after referenced one
-*/
-struct tipc_sock *tipc_sk_get_next(u32 *ref)
+void tipc_sk_rht_destroy(void)
 {
-	struct reference *entry;
-	struct tipc_sock *tsk = NULL;
-	uint index = *ref & tipc_ref_table.index_mask;
+	/* Wait for socket readers to complete */
+	synchronize_net();
 
-	read_lock_bh(&ref_table_lock);
-	while (++index < tipc_ref_table.capacity) {
-		entry = &tipc_ref_table.entries[index];
-		if (!entry->tsk)
-			continue;
-		tsk = entry->tsk;
-		sock_hold(&tsk->sk);
-		*ref = entry->ref;
-		break;
-	}
-	read_unlock_bh(&ref_table_lock);
-	return tsk;
-}
-
-static void tipc_sk_put(struct tipc_sock *tsk)
-{
-	sock_put(&tsk->sk);
+	rhashtable_destroy(&tipc_sk_rht);
 }
 
 /**
@@ -2829,7 +2684,7 @@ static int __tipc_nl_add_sk(struct sk_buff *skb, struct netlink_callback *cb,
 	attrs = nla_nest_start(skb, TIPC_NLA_SOCK);
 	if (!attrs)
 		goto genlmsg_cancel;
-	if (nla_put_u32(skb, TIPC_NLA_SOCK_REF, tsk->ref))
+	if (nla_put_u32(skb, TIPC_NLA_SOCK_REF, tsk->portid))
 		goto attr_msg_cancel;
 	if (nla_put_u32(skb, TIPC_NLA_SOCK_ADDR, tipc_own_addr))
 		goto attr_msg_cancel;
@@ -2859,22 +2714,29 @@ int tipc_nl_sk_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	int err;
 	struct tipc_sock *tsk;
-	u32 prev_ref = cb->args[0];
-	u32 ref = prev_ref;
-
-	tsk = tipc_sk_get_next(&ref);
-	for (; tsk; tsk = tipc_sk_get_next(&ref)) {
-		lock_sock(&tsk->sk);
-		err = __tipc_nl_add_sk(skb, cb, tsk);
-		release_sock(&tsk->sk);
-		tipc_sk_put(tsk);
-		if (err)
-			break;
+	const struct bucket_table *tbl;
+	struct rhash_head *pos;
+	u32 prev_portid = cb->args[0];
+	u32 portid = prev_portid;
+	int i;
 
-		prev_ref = ref;
+	rcu_read_lock();
+	tbl = rht_dereference_rcu((&tipc_sk_rht)->tbl, &tipc_sk_rht);
+	for (i = 0; i < tbl->size; i++) {
+		rht_for_each_entry_rcu(tsk, pos, tbl, i, node) {
+			spin_lock_bh(&tsk->sk.sk_lock.slock);
+			portid = tsk->portid;
+			err = __tipc_nl_add_sk(skb, cb, tsk);
+			spin_unlock_bh(&tsk->sk.sk_lock.slock);
+			if (err)
+				break;
+
+			prev_portid = portid;
+		}
 	}
+	rcu_read_unlock();
 
-	cb->args[0] = prev_ref;
+	cb->args[0] = prev_portid;
 
 	return skb->len;
 }
@@ -2962,12 +2824,12 @@ static int __tipc_nl_list_sk_publ(struct sk_buff *skb,
 int tipc_nl_publ_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	int err;
-	u32 tsk_ref = cb->args[0];
+	u32 tsk_portid = cb->args[0];
 	u32 last_publ = cb->args[1];
 	u32 done = cb->args[2];
 	struct tipc_sock *tsk;
 
-	if (!tsk_ref) {
+	if (!tsk_portid) {
 		struct nlattr **attrs;
 		struct nlattr *sock[TIPC_NLA_SOCK_MAX + 1];
 
@@ -2984,13 +2846,13 @@ int tipc_nl_publ_dump(struct sk_buff *skb, struct netlink_callback *cb)
 		if (!sock[TIPC_NLA_SOCK_REF])
 			return -EINVAL;
 
-		tsk_ref = nla_get_u32(sock[TIPC_NLA_SOCK_REF]);
+		tsk_portid = nla_get_u32(sock[TIPC_NLA_SOCK_REF]);
 	}
 
 	if (done)
 		return 0;
 
-	tsk = tipc_sk_get(tsk_ref);
+	tsk = tipc_sk_lookup(tsk_portid);
 	if (!tsk)
 		return -EINVAL;
 
@@ -2999,9 +2861,9 @@ int tipc_nl_publ_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	if (!err)
 		done = 1;
 	release_sock(&tsk->sk);
-	tipc_sk_put(tsk);
+	sock_put(&tsk->sk);
 
-	cb->args[0] = tsk_ref;
+	cb->args[0] = tsk_portid;
 	cb->args[1] = last_publ;
 	cb->args[2] = done;