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authorAllan Stephens <allan.stephens@windriver.com>2008-05-21 17:53:00 -0400
committerDavid S. Miller <davem@davemloft.net>2008-05-21 17:53:00 -0400
commit2ecb0924d7791372a70ef8f1174e37b329b955c3 (patch)
tree70325c7aacda9e2076fe86664938bf5d794095ed /net/tipc
parent59f0c4523fdea865fab7d69d878269992a9d08dd (diff)
tipc: Prevent node object duplication due to simultaneous discovery
This patch ensures that the simultaneous discovery of the same neighboring node by multiple interfaces does not cause TIPC to add the node into its internal data structures more than once. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc')
-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 598f4d3a0098..34e9a2bb7c19 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -52,16 +52,40 @@ static void node_established_contact(struct node *n_ptr);
52 52
53struct node *tipc_nodes = NULL; /* sorted list of nodes within cluster */ 53struct node *tipc_nodes = NULL; /* sorted list of nodes within cluster */
54 54
55static DEFINE_SPINLOCK(node_create_lock);
56
55u32 tipc_own_tag = 0; 57u32 tipc_own_tag = 0;
56 58
59/**
60 * tipc_node_create - create neighboring node
61 *
62 * Currently, this routine is called by neighbor discovery code, which holds
63 * net_lock for reading only. We must take node_create_lock to ensure a node
64 * isn't created twice if two different bearers discover the node at the same
65 * time. (It would be preferable to switch to holding net_lock in write mode,
66 * but this is a non-trivial change.)
67 */
68
57struct node *tipc_node_create(u32 addr) 69struct node *tipc_node_create(u32 addr)
58{ 70{
59 struct cluster *c_ptr; 71 struct cluster *c_ptr;
60 struct node *n_ptr; 72 struct node *n_ptr;
61 struct node **curr_node; 73 struct node **curr_node;
62 74
75 spin_lock_bh(&node_create_lock);
76
77 for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
78 if (addr < n_ptr->addr)
79 break;
80 if (addr == n_ptr->addr) {
81 spin_unlock_bh(&node_create_lock);
82 return n_ptr;
83 }
84 }
85
63 n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC); 86 n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
64 if (!n_ptr) { 87 if (!n_ptr) {
88 spin_unlock_bh(&node_create_lock);
65 warn("Node creation failed, no memory\n"); 89 warn("Node creation failed, no memory\n");
66 return NULL; 90 return NULL;
67 } 91 }
@@ -71,6 +95,7 @@ struct node *tipc_node_create(u32 addr)
71 c_ptr = tipc_cltr_create(addr); 95 c_ptr = tipc_cltr_create(addr);
72 } 96 }
73 if (!c_ptr) { 97 if (!c_ptr) {
98 spin_unlock_bh(&node_create_lock);
74 kfree(n_ptr); 99 kfree(n_ptr);
75 return NULL; 100 return NULL;
76 } 101 }
@@ -91,6 +116,7 @@ struct node *tipc_node_create(u32 addr)
91 } 116 }
92 } 117 }
93 (*curr_node) = n_ptr; 118 (*curr_node) = n_ptr;
119 spin_unlock_bh(&node_create_lock);
94 return n_ptr; 120 return n_ptr;
95} 121}
96 122