tipc: remove pre-allocated message header in link struct

Until now, we have kept a pre-allocated protocol message header
aggregated into struct tipc_link. Apart from adding unnecessary
footprint to the link instances, this requires extra code both to
initialize and re-initialize it.

We now remove this sub-optimization. This change also makes it
possible to clean up the function tipc_build_proto_msg() and remove
a couple of small functions that were accessing the mentioned header.
In particular, we can replace all occurrences of the local function
call link_own_addr(link) with the generic tipc_own_addr(net).
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/bcast.c

@@ -412,11 +412,6 @@ int tipc_bcast_init(struct net *net)
 	return -ENOMEM;
 }
 
-void tipc_bcast_reinit(struct net *net)
-{
-	tipc_link_reinit(tipc_bc_sndlink(net), tipc_own_addr(net));
-}
-
 void tipc_bcast_stop(struct net *net)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);

net/tipc/bcast.h

@@ -46,7 +46,6 @@ struct tipc_node_map;
 extern const char tipc_bclink_name[];
 
 int tipc_bcast_init(struct net *net);
-void tipc_bcast_reinit(struct net *net);
 void tipc_bcast_stop(struct net *net);
 void tipc_bcast_add_peer(struct net *net, struct tipc_link *l,
 			 struct sk_buff_head *xmitq);

net/tipc/link.c

 /*
  * net/tipc/link.c: TIPC link code
  *
- * Copyright (c) 1996-2007, 2012-2015, Ericsson AB
+ * Copyright (c) 1996-2007, 2012-2016, Ericsson AB
  * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
  * All rights reserved.
  *
@@ -127,6 +127,7 @@ struct tipc_link {
 
 	/* Management and link supervision data */
 	u32 peer_session;
+	u32 session;
 	u32 peer_bearer_id;
 	u32 bearer_id;
 	u32 tolerance;
@@ -136,11 +137,7 @@ struct tipc_link {
 	u16 peer_caps;
 	bool active;
 	u32 silent_intv_cnt;
-	struct {
-		unchar hdr[INT_H_SIZE];
-		unchar body[TIPC_MAX_IF_NAME];
-	} proto_msg;
-	struct tipc_msg *pmsg;
+	char if_name[TIPC_MAX_IF_NAME];
 	u32 priority;
 	char net_plane;
 
@@ -215,10 +212,11 @@ enum {
  * Interval between NACKs when packets arrive out of order
  */
 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
-/*
- * Out-of-range value for link session numbers
+
+/* Wildcard value for link session numbers. When it is known that
+ * peer endpoint is down, any session number must be accepted.
  */
-#define WILDCARD_SESSION 0x10000
+#define ANY_SESSION 0x10000
 
 /* Link FSM states:
  */
@@ -398,16 +396,6 @@ char *tipc_link_name(struct tipc_link *l)
 	return l->name;
 }
 
-static u32 link_own_addr(struct tipc_link *l)
-{
-	return msg_prevnode(l->pmsg);
-}
-
-void tipc_link_reinit(struct tipc_link *l, u32 addr)
-{
-	msg_set_prevnode(l->pmsg, addr);
-}
-
 /**
  * tipc_link_create - create a new link
  * @n: pointer to associated node
@@ -441,29 +429,22 @@ bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
 		      struct tipc_link **link)
 {
 	struct tipc_link *l;
-	struct tipc_msg *hdr;
 
 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
 	if (!l)
 		return false;
 	*link = l;
-	l->pmsg = (struct tipc_msg *)&l->proto_msg;
-	hdr = l->pmsg;
-	tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
-	msg_set_size(hdr, sizeof(l->proto_msg));
-	msg_set_session(hdr, session);
-	msg_set_bearer_id(hdr, l->bearer_id);
+	l->session = session;
 
 	/* Note: peer i/f name is completed by reset/activate message */
 	sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 		tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
 		if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
-	strcpy((char *)msg_data(hdr), if_name);
-
+	strcpy(l->if_name, if_name);
 	l->addr = peer;
 	l->peer_caps = peer_caps;
 	l->net = net;
-	l->peer_session = WILDCARD_SESSION;
+	l->peer_session = ANY_SESSION;
 	l->bearer_id = bearer_id;
 	l->tolerance = tolerance;
 	l->net_plane = net_plane;
@@ -790,7 +771,7 @@ static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 	struct tipc_msg *msg = buf_msg(skb_peek(list));
 	int imp = msg_importance(msg);
 	u32 oport = msg_origport(msg);
-	u32 addr = link_own_addr(link);
+	u32 addr = tipc_own_addr(link->net);
 	struct sk_buff *skb;
 
 	/* This really cannot happen...  */
@@ -839,16 +820,9 @@ void link_prepare_wakeup(struct tipc_link *l)
 
 void tipc_link_reset(struct tipc_link *l)
 {
-	/* Link is down, accept any session */
-	l->peer_session = WILDCARD_SESSION;
-
-	/* If peer is up, it only accepts an incremented session number */
-	msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
-
-	/* Prepare for renewed mtu size negotiation */
+	l->peer_session = ANY_SESSION;
+	l->session++;
 	l->mtu = l->advertised_mtu;
-
-	/* Clean up all queues and counters: */
 	__skb_queue_purge(&l->transmq);
 	__skb_queue_purge(&l->deferdq);
 	skb_queue_splice_init(&l->wakeupq, l->inputq);
@@ -1156,7 +1130,7 @@ int tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
 
 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
 	if (link_is_bc_rcvlink(l)) {
-		if (((l->rcv_nxt ^ link_own_addr(l)) & 0xf) != 0xf)
+		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
 			return 0;
 		l->rcv_unacked = 0;
 		return TIPC_LINK_SND_BC_ACK;
@@ -1268,15 +1242,30 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 				      u16 rcvgap, int tolerance, int priority,
 				      struct sk_buff_head *xmitq)
 {
-	struct sk_buff *skb = NULL;
-	struct tipc_msg *hdr = l->pmsg;
+	struct sk_buff *skb;
+	struct tipc_msg *hdr;
+	struct sk_buff_head *dfq = &l->deferdq;
 	bool node_up = link_is_up(l->bc_rcvlink);
 
 	/* Don't send protocol message during reset or link failover */
 	if (tipc_link_is_blocked(l))
 		return;
 
-	msg_set_type(hdr, mtyp);
+	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
+		return;
+
+	if (!skb_queue_empty(dfq))
+		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
+
+	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
+			      TIPC_MAX_IF_NAME, l->addr,
+			      tipc_own_addr(l->net), 0, 0, 0);
+	if (!skb)
+		return;
+
+	hdr = buf_msg(skb);
+	msg_set_session(hdr, l->session);
+	msg_set_bearer_id(hdr, l->bearer_id);
 	msg_set_net_plane(hdr, l->net_plane);
 	msg_set_next_sent(hdr, l->snd_nxt);
 	msg_set_ack(hdr, l->rcv_nxt - 1);
@@ -1286,36 +1275,23 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 	msg_set_linkprio(hdr, priority);
 	msg_set_redundant_link(hdr, node_up);
 	msg_set_seq_gap(hdr, 0);
-
-	/* Compatibility: created msg must not be in sequence with pkt flow */
 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
 
 	if (mtyp == STATE_MSG) {
-		if (!tipc_link_is_up(l))
-			return;
-
-		/* Override rcvgap if there are packets in deferred queue */
-		if (!skb_queue_empty(&l->deferdq))
-			rcvgap = buf_seqno(skb_peek(&l->deferdq)) - l->rcv_nxt;
-		if (rcvgap) {
 		msg_set_seq_gap(hdr, rcvgap);
-			l->stats.sent_nacks++;
-		}
+		msg_set_size(hdr, INT_H_SIZE);
 		msg_set_probe(hdr, probe);
-		if (probe)
-			l->stats.sent_probes++;
 		l->stats.sent_states++;
 		l->rcv_unacked = 0;
 	} else {
 		/* RESET_MSG or ACTIVATE_MSG */
 		msg_set_max_pkt(hdr, l->advertised_mtu);
-		msg_set_ack(hdr, l->rcv_nxt - 1);
-		msg_set_next_sent(hdr, 1);
+		strcpy(msg_data(hdr), l->if_name);
 	}
-	skb = tipc_buf_acquire(msg_size(hdr));
-	if (!skb)
-		return;
-	skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
+	if (probe)
+		l->stats.sent_probes++;
+	if (rcvgap)
+		l->stats.sent_nacks++;
 	skb->priority = TC_PRIO_CONTROL;
 	__skb_queue_tail(xmitq, skb);
 }
@@ -1340,7 +1316,7 @@ void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
 
 	/* At least one packet required for safe algorithm => add dummy */
 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
-			      BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
+			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
 			      0, 0, TIPC_ERR_NO_PORT);
 	if (!skb) {
 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
@@ -1351,7 +1327,7 @@ void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
 	__skb_queue_purge(&tmpxq);
 
 	/* Initialize reusable tunnel packet header */
-	tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
+	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
 		      mtyp, INT_H_SIZE, l->addr);
 	pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
 	msg_set_msgcnt(&tnlhdr, pktcnt);
@@ -1410,7 +1386,7 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 	if (tipc_link_is_blocked(l) || !xmitq)
 		goto exit;
 
-	if (link_own_addr(l) > msg_prevnode(hdr))
+	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
 		l->net_plane = msg_net_plane(hdr);
 
 	switch (mtyp) {
@@ -1418,7 +1394,7 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 
 		/* Ignore duplicate RESET with old session number */
 		if ((less_eq(msg_session(hdr), l->peer_session)) &&
-		    (l->peer_session != WILDCARD_SESSION))
+		    (l->peer_session != ANY_SESSION))
 			break;
 		/* fall thru' */
 
@@ -1515,7 +1491,7 @@ static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
 	u16 gap_to = peers_snd_nxt - 1;
 
 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
-			      0, l->addr, link_own_addr(l), 0, 0, 0);
+			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
 	if (!skb)
 		return false;
 	hdr = buf_msg(skb);
@@ -1670,7 +1646,7 @@ int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
 	if (mtyp != STATE_MSG)
 		return 0;
 
-	if (dnode == link_own_addr(l)) {
+	if (dnode == tipc_own_addr(l->net)) {
 		tipc_link_bc_ack_rcv(l, acked, xmitq);
 		rc = tipc_link_retrans(l->bc_sndlink, from, to, xmitq);
 		l->stats.recv_nacks++;

net/tipc/link.h

@@ -86,7 +86,6 @@ bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
 			 struct sk_buff_head *namedq,
 			 struct tipc_link *bc_sndlink,
 			 struct tipc_link **link);
-void tipc_link_reinit(struct tipc_link *l, u32 addr);
 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
 			   int mtyp, struct sk_buff_head *xmitq);
 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq);

net/tipc/net.c

@@ -116,7 +116,6 @@ int tipc_net_start(struct net *net, u32 addr)
 	tn->own_addr = addr;
 	tipc_named_reinit(net);
 	tipc_sk_reinit(net);
-	tipc_bcast_reinit(net);
 
 	tipc_nametbl_publish(net, TIPC_CFG_SRV, tn->own_addr, tn->own_addr,
 			     TIPC_ZONE_SCOPE, 0, tn->own_addr);