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authorAllan Stephens <allan.stephens@windriver.com>2011-04-07 13:57:25 -0400
committerPaul Gortmaker <paul.gortmaker@windriver.com>2011-09-01 11:16:36 -0400
commit5d3c488dfe5f797d9f3cee2e8928aad8a2f6e44f (patch)
tree93e9f59a4ad2c155939b6f66ca30d1e9201fff87 /net/tipc
parent169073db442cb9e5aa2b70a2e4158d4f35a3b810 (diff)
tipc: Fix node lock problems during broadcast message reception
Modifies TIPC's incoming broadcast packet handler to ensure that the node lock associated with the sender of the packet is held whenever node-related data structure fields are accessed. The routine is also restructured with a single exit point, making it easier to ensure the node lock is properly released and the incoming packet is properly disposed of. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'net/tipc')
-rw-r--r--net/tipc/bcast.c36
1 files changed, 23 insertions, 13 deletions
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 5200457eaeb4..bc01ca6891e4 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -426,20 +426,26 @@ int tipc_bclink_send_msg(struct sk_buff *buf)
void tipc_bclink_recv_pkt(struct sk_buff *buf)
{
struct tipc_msg *msg = buf_msg(buf);
- struct tipc_node *node = tipc_node_find(msg_prevnode(msg));
+ struct tipc_node *node;
u32 next_in;
u32 seqno;
struct sk_buff *deferred;
- if (unlikely(!node || !tipc_node_is_up(node) || !node->bclink.supported ||
- (msg_mc_netid(msg) != tipc_net_id))) {
- buf_discard(buf);
- return;
- }
+ /* Screen out unwanted broadcast messages */
+
+ if (msg_mc_netid(msg) != tipc_net_id)
+ goto exit;
+
+ node = tipc_node_find(msg_prevnode(msg));
+ if (unlikely(!node))
+ goto exit;
+
+ tipc_node_lock(node);
+ if (unlikely(!node->bclink.supported))
+ goto unlock;
if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) {
if (msg_destnode(msg) == tipc_own_addr) {
- tipc_node_lock(node);
tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
tipc_node_unlock(node);
spin_lock_bh(&bc_lock);
@@ -449,16 +455,17 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf)
msg_bcgap_to(msg));
spin_unlock_bh(&bc_lock);
} else {
+ tipc_node_unlock(node);
tipc_bclink_peek_nack(msg_destnode(msg),
msg_bcast_tag(msg),
msg_bcgap_after(msg),
msg_bcgap_to(msg));
}
- buf_discard(buf);
- return;
+ goto exit;
}
- tipc_node_lock(node);
+ /* Handle in-sequence broadcast message */
+
receive:
deferred = node->bclink.deferred_head;
next_in = mod(node->bclink.last_in + 1);
@@ -491,14 +498,14 @@ receive:
tipc_node_unlock(node);
tipc_net_route_msg(buf);
}
+ buf = NULL;
+ tipc_node_lock(node);
if (deferred && (buf_seqno(deferred) == mod(next_in + 1))) {
- tipc_node_lock(node);
buf = deferred;
msg = buf_msg(buf);
node->bclink.deferred_head = deferred->next;
goto receive;
}
- return;
} else if (less(next_in, seqno)) {
u32 gap_after = node->bclink.gap_after;
u32 gap_to = node->bclink.gap_to;
@@ -513,6 +520,7 @@ receive:
else if (less(gap_after, seqno) && less(seqno, gap_to))
node->bclink.gap_to = seqno;
}
+ buf = NULL;
if (bclink_ack_allowed(node->bclink.nack_sync)) {
if (gap_to != gap_after)
bclink_send_nack(node);
@@ -520,9 +528,11 @@ receive:
}
} else {
bcl->stats.duplicates++;
- buf_discard(buf);
}
+unlock:
tipc_node_unlock(node);
+exit:
+ buf_discard(buf);
}
u32 tipc_bclink_acks_missing(struct tipc_node *n_ptr)