[net-next 2/3] tipc: modify struct tipc_plist to be more versatile

[Jon Maloy <jon.maloy@ericsson.com>]

During multicast reception we currently use a simple linked list with
push/pop semantics to store port numbers.

We now see a need for a more generic list for storing values of type
u32. We therefore make some modifications to this list, while replacing
the prefix 'tipc_plist_' with 'u32_'. We also add a couple of new
functions which will come to use in the next commits.

Acked-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
---
 net/tipc/name_table.c | 100 ++++++++++++++++++++++++++++++++++++--------------
 net/tipc/name_table.h |  21 ++++-------
 net/tipc/socket.c     |   8 ++--
 3 files changed, 83 insertions(+), 46 deletions(-)

diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index e190460..5a86df1 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -608,7 +608,7 @@ u32 tipc_nametbl_translate(struct net *net, u32 type, u32 instance,
  * Returns non-zero if any off-node ports overlap
  */
 int tipc_nametbl_mc_translate(struct net *net, u32 type, u32 lower, u32 upper,
-			      u32 limit, struct tipc_plist *dports)
+			      u32 limit, struct list_head *dports)
 {
 	struct name_seq *seq;
 	struct sub_seq *sseq;
@@ -633,7 +633,7 @@ int tipc_nametbl_mc_translate(struct net *net, u32 type, u32 lower, u32 upper,
 		info = sseq->info;
 		list_for_each_entry(publ, &info->node_list, node_list) {
 			if (publ->scope <= limit)
-				tipc_plist_push(dports, publ->ref);
+				u32_push(dports, publ->ref);
 		}
 
 		if (info->cluster_list_size != info->node_list_size)
@@ -1022,40 +1022,84 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
-void tipc_plist_push(struct tipc_plist *pl, u32 port)
+struct u32_item {
+	struct list_head list;
+	u32 value;
+};
+
+bool u32_find(struct list_head *l, u32 value)
 {
-	struct tipc_plist *nl;
+	struct u32_item *item;
 
-	if (likely(!pl->port)) {
-		pl->port = port;
-		return;
+	list_for_each_entry(item, l, list) {
+		if (item->value == value)
+			return true;
 	}
-	if (pl->port == port)
-		return;
-	list_for_each_entry(nl, &pl->list, list) {
-		if (nl->port == port)
-			return;
+	return false;
+}
+
+bool u32_push(struct list_head *l, u32 value)
+{
+	struct u32_item *item;
+
+	list_for_each_entry(item, l, list) {
+		if (item->value == value)
+			return false;
+	}
+	item = kmalloc(sizeof(*item), GFP_ATOMIC);
+	if (unlikely(!item))
+		return false;
+
+	item->value = value;
+	list_add(&item->list, l);
+	return true;
+}
+
+u32 u32_pop(struct list_head *l)
+{
+	struct u32_item *item;
+	u32 value = 0;
+
+	if (list_empty(l))
+		return 0;
+	item = list_first_entry(l, typeof(*item), list);
+	value = item->value;
+	list_del(&item->list);
+	kfree(item);
+	return value;
+}
+
+bool u32_del(struct list_head *l, u32 value)
+{
+	struct u32_item *item, *tmp;
+
+	list_for_each_entry_safe(item, tmp, l, list) {
+		if (item->value != value)
+			continue;
+		list_del(&item->list);
+		kfree(item);
+		return true;
 	}
-	nl = kmalloc(sizeof(*nl), GFP_ATOMIC);
-	if (nl) {
-		nl->port = port;
-		list_add(&nl->list, &pl->list);
+	return false;
+}
+
+void u32_list_purge(struct list_head *l)
+{
+	struct u32_item *item, *tmp;
+
+	list_for_each_entry_safe(item, tmp, l, list) {
+		list_del(&item->list);
+		kfree(item);
 	}
 }
 
-u32 tipc_plist_pop(struct tipc_plist *pl)
+int u32_list_len(struct list_head *l)
 {
-	struct tipc_plist *nl;
-	u32 port = 0;
+	struct u32_item *item;
+	int i = 0;
 
-	if (likely(list_empty(&pl->list))) {
-		port = pl->port;
-		pl->port = 0;
-		return port;
+	list_for_each_entry(item, l, list) {
+		i++;
 	}
-	nl = list_first_entry(&pl->list, typeof(*nl), list);
-	port = nl->port;
-	list_del(&nl->list);
-	kfree(nl);
-	return port;
+	return i;
 }
diff --git a/net/tipc/name_table.h b/net/tipc/name_table.h
index 1524a73..c89bb3f 100644
--- a/net/tipc/name_table.h
+++ b/net/tipc/name_table.h
@@ -99,7 +99,7 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb);
 
 u32 tipc_nametbl_translate(struct net *net, u32 type, u32 instance, u32 *node);
 int tipc_nametbl_mc_translate(struct net *net, u32 type, u32 lower, u32 upper,
-			      u32 limit, struct tipc_plist *dports);
+			      u32 limit, struct list_head *dports);
 struct publication *tipc_nametbl_publish(struct net *net, u32 type, u32 lower,
 					 u32 upper, u32 scope, u32 port_ref,
 					 u32 key);
@@ -116,18 +116,11 @@ void tipc_nametbl_unsubscribe(struct tipc_subscription *s);
 int tipc_nametbl_init(struct net *net);
 void tipc_nametbl_stop(struct net *net);
 
-struct tipc_plist {
-	struct list_head list;
-	u32 port;
-};
-
-static inline void tipc_plist_init(struct tipc_plist *pl)
-{
-	INIT_LIST_HEAD(&pl->list);
-	pl->port = 0;
-}
-
-void tipc_plist_push(struct tipc_plist *pl, u32 port);
-u32 tipc_plist_pop(struct tipc_plist *pl);
+bool u32_push(struct list_head *l, u32 value);
+u32 u32_pop(struct list_head *l);
+bool u32_find(struct list_head *l, u32 value);
+bool u32_del(struct list_head *l, u32 value);
+void u32_list_purge(struct list_head *l);
+int u32_list_len(struct list_head *l);
 
 #endif
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index f27462e..fae6a55 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -788,7 +788,7 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
 		       struct sk_buff_head *inputq)
 {
 	struct tipc_msg *msg;
-	struct tipc_plist dports;
+	struct list_head dports;
 	u32 portid;
 	u32 scope = TIPC_CLUSTER_SCOPE;
 	struct sk_buff_head tmpq;
@@ -796,7 +796,7 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
 	struct sk_buff *skb, *_skb;
 
 	__skb_queue_head_init(&tmpq);
-	tipc_plist_init(&dports);
+	INIT_LIST_HEAD(&dports);
 
 	skb = tipc_skb_peek(arrvq, &inputq->lock);
 	for (; skb; skb = tipc_skb_peek(arrvq, &inputq->lock)) {
@@ -810,8 +810,8 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
 		tipc_nametbl_mc_translate(net,
 					  msg_nametype(msg), msg_namelower(msg),
 					  msg_nameupper(msg), scope, &dports);
-		portid = tipc_plist_pop(&dports);
-		for (; portid; portid = tipc_plist_pop(&dports)) {
+		portid = u32_pop(&dports);
+		for (; portid; portid = u32_pop(&dports)) {
 			_skb = __pskb_copy(skb, hsz, GFP_ATOMIC);
 			if (_skb) {
 				msg_set_destport(buf_msg(_skb), portid);
-- 
2.7.4