tipc: Optimizations to link creation code

Enhances link creation code as follows:

1) Detects illegal attempts to add a requested link earlier in the
   link creation process. This prevents TIPC from wasting time
   initializing a link object it then throws away, and also eliminates
   the code needed to do the throwing away.

2) Passes in the node object associated with the requested link.
   This allows TIPC to eliminate a search to locate the node object,
   as well as code that attempted to create the node if it doesn't
   exist.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

1 files changed, 20 insertions, 7 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index e5f96d5ef1a..b73adeb5cde 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -293,19 +293,35 @@ static void link_set_timer(struct link *l_ptr, u32 time)
 
 /**
  * tipc_link_create - create a new link
+ * @n_ptr: pointer to associated node
  * @b_ptr: pointer to associated bearer
- * @peer: network address of node at other end of link
  * @media_addr: media address to use when sending messages over link
  *
  * Returns pointer to link.
  */
 
-struct link *tipc_link_create(struct tipc_bearer *b_ptr, const u32 peer,
+struct link *tipc_link_create(struct tipc_node *n_ptr,
+			      struct tipc_bearer *b_ptr,
 			      const struct tipc_media_addr *media_addr)
 {
 	struct link *l_ptr;
 	struct tipc_msg *msg;
 	char *if_name;
+	char addr_string[16];
+	u32 peer = n_ptr->addr;
+
+	if (n_ptr->link_cnt >= 2) {
+		tipc_addr_string_fill(addr_string, n_ptr->addr);
+		err("Attempt to establish third link to %s\n", addr_string);
+		return NULL;
+	}
+
+	if (n_ptr->links[b_ptr->identity]) {
+		tipc_addr_string_fill(addr_string, n_ptr->addr);
+		err("Attempt to establish second link on <%s> to %s\n",
+		    b_ptr->name, addr_string);
+		return NULL;
+	}
 
 	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 	if (!l_ptr) {
@@ -322,6 +338,7 @@ struct link *tipc_link_create(struct tipc_bearer *b_ptr, const u32 peer,
 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 		/* note: peer i/f is appended to link name by reset/activate */
 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
+	l_ptr->owner = n_ptr;
 	l_ptr->checkpoint = 1;
 	l_ptr->b_ptr = b_ptr;
 	link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
@@ -345,11 +362,7 @@ struct link *tipc_link_create(struct tipc_bearer *b_ptr, const u32 peer,
 
 	link_reset_statistics(l_ptr);
 
-	l_ptr->owner = tipc_node_attach_link(l_ptr);
-	if (!l_ptr->owner) {
-		kfree(l_ptr);
-		return NULL;
-	}
+	tipc_node_attach_link(n_ptr, l_ptr);
 
 	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 	list_add_tail(&l_ptr->link_list, &b_ptr->links);