tipc: Add missing locks in broadcast link statistics accumulation
Allan Stephens [Wed, 26 Oct 2011 20:13:35 +0000 (16:13 -0400)]
Ensures that all attempts to update broadcast link statistics are done
only while holding the lock that protects the link's main data structures,
to prevent interference by simultaneous updates caused by messages
arriving on other interfaces.

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

net/tipc/bcast.c

index 035b350..facc216 100644 (file)
@@ -520,6 +520,7 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf)
 
        if (likely(seqno == next_in)) {
 receive:
+               spin_lock_bh(&bc_lock);
                bcl->stats.recv_info++;
                node->bclink.last_in++;
                bclink_set_gap(node);
@@ -527,7 +528,9 @@ receive:
                        bclink_send_ack(node);
                        bcl->stats.sent_acks++;
                }
+
                if (likely(msg_isdata(msg))) {
+                       spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        if (likely(msg_mcast(msg)))
                                tipc_port_recv_mcast(buf, NULL);
@@ -536,6 +539,7 @@ receive:
                } else if (msg_user(msg) == MSG_BUNDLER) {
                        bcl->stats.recv_bundles++;
                        bcl->stats.recv_bundled += msg_msgcnt(msg);
+                       spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        tipc_link_recv_bundle(buf);
                } else if (msg_user(msg) == MSG_FRAGMENTER) {
@@ -543,12 +547,15 @@ receive:
                        if (tipc_link_recv_fragment(&node->bclink.defragm,
                                                    &buf, &msg))
                                bcl->stats.recv_fragmented++;
+                       spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        tipc_net_route_msg(buf);
                } else if (msg_user(msg) == NAME_DISTRIBUTOR) {
+                       spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        tipc_named_recv(buf);
                } else {
+                       spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        buf_discard(buf);
                }
@@ -601,11 +608,15 @@ receive:
        } else
                deferred = 0;
 
+       spin_lock_bh(&bc_lock);
+
        if (deferred)
                bcl->stats.deferred_recv++;
        else
                bcl->stats.duplicates++;
 
+       spin_unlock_bh(&bc_lock);
+
 unlock:
        tipc_node_unlock(node);
 exit: