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-rw-r--r--net/tipc/node.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 598f4d3a009..34e9a2bb7c1 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -52,16 +52,40 @@ static void node_established_contact(struct node *n_ptr);
struct node *tipc_nodes = NULL; /* sorted list of nodes within cluster */
+static DEFINE_SPINLOCK(node_create_lock);
+
u32 tipc_own_tag = 0;
+/**
+ * tipc_node_create - create neighboring node
+ *
+ * Currently, this routine is called by neighbor discovery code, which holds
+ * net_lock for reading only. We must take node_create_lock to ensure a node
+ * isn't created twice if two different bearers discover the node at the same
+ * time. (It would be preferable to switch to holding net_lock in write mode,
+ * but this is a non-trivial change.)
+ */
+
struct node *tipc_node_create(u32 addr)
{
struct cluster *c_ptr;
struct node *n_ptr;
struct node **curr_node;
+ spin_lock_bh(&node_create_lock);
+
+ for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
+ if (addr < n_ptr->addr)
+ break;
+ if (addr == n_ptr->addr) {
+ spin_unlock_bh(&node_create_lock);
+ return n_ptr;
+ }
+ }
+
n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
if (!n_ptr) {
+ spin_unlock_bh(&node_create_lock);
warn("Node creation failed, no memory\n");
return NULL;
}
@@ -71,6 +95,7 @@ struct node *tipc_node_create(u32 addr)
c_ptr = tipc_cltr_create(addr);
}
if (!c_ptr) {
+ spin_unlock_bh(&node_create_lock);
kfree(n_ptr);
return NULL;
}
@@ -91,6 +116,7 @@ struct node *tipc_node_create(u32 addr)
}
}
(*curr_node) = n_ptr;
+ spin_unlock_bh(&node_create_lock);
return n_ptr;
}