netdev - [net 4/4] tipc: make function tipc_net

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Date:   Fri, 6 Jul 2018 20:10:06 +0200
From:   Jon Maloy <jon.maloy@...csson.com>
To:     <davem@...emloft.net>, <netdev@...r.kernel.org>
CC:     <gordan.mihaljevic@...tech.com.au>, <tung.q.nguyen@...tech.com.au>,
        <hoang.h.le@...tech.com.au>, <jon.maloy@...csson.com>,
        <canh.d.luu@...tech.com.au>, <ying.xue@...driver.com>,
        <tipc-discussion@...ts.sourceforge.net>
Subject: [net 4/4] tipc: make function tipc_net_finalize() thread safe

The setting of the node address is not thread safe, meaning that
two discoverers may decide to set it simultanously, with a duplicate
entry in the name table as result. We fix that with this commit.

Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values")
Signed-off-by: Jon Maloy <jon.maloy@...csson.com>
---
 net/tipc/net.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/net/tipc/net.c b/net/tipc/net.c
index 4fbaa04..a7f6964 100644
--- a/net/tipc/net.c
+++ b/net/tipc/net.c
@@ -121,12 +121,17 @@ int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
 
 void tipc_net_finalize(struct net *net, u32 addr)
 {
-	tipc_set_node_addr(net, addr);
-	smp_mb();
-	tipc_named_reinit(net);
-	tipc_sk_reinit(net);
-	tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
-			     TIPC_CLUSTER_SCOPE, 0, addr);
+	struct tipc_net *tn = tipc_net(net);
+
+	spin_lock_bh(&tn->node_list_lock);
+	if (!tipc_own_addr(net)) {
+		tipc_set_node_addr(net, addr);
+		tipc_named_reinit(net);
+		tipc_sk_reinit(net);
+		tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
+				     TIPC_CLUSTER_SCOPE, 0, addr);
+	}
+	spin_unlock_bh(&tn->node_list_lock);
 }
 
 void tipc_net_stop(struct net *net)
-- 
2.1.4