[AX.25]: Fix unchecked ax25_listen_register uses

Fix ax25_listen_register to return something that's a sane error code,
then all callers to use it.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 6 deletions

diff --git a/net/netrom/nr_dev.c b/net/netrom/nr_dev.c
index 9b8eb54971ab..4700d5225b78 100644
--- a/net/netrom/nr_dev.c
+++ b/net/netrom/nr_dev.c
@@ -128,25 +128,37 @@ static int nr_header(struct sk_buff *skb, struct net_device *dev, unsigned short
         return -37;
 }
 
-static int nr_set_mac_address(struct net_device *dev, void *addr)
+static int __must_check nr_set_mac_address(struct net_device *dev, void *addr)
 {
         struct sockaddr *sa = addr;
+        int err;
+
+        if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
+                return 0;
+
+        if (dev->flags & IFF_UP) {
+                err = ax25_listen_register((ax25_address *)sa->sa_data, NULL);
+                if (err)
+                        return err;
 
-        if (dev->flags & IFF_UP)
                 ax25_listen_release((ax25_address *)dev->dev_addr, NULL);
+        }
 
         memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 
-        if (dev->flags & IFF_UP)
-                ax25_listen_register((ax25_address *)dev->dev_addr, NULL);
-
         return 0;
 }
 
 static int nr_open(struct net_device *dev)
 {
+        int err;
+
+        err = ax25_listen_register((ax25_address *)dev->dev_addr, NULL);
+        if (err)
+                return err;
+
         netif_start_queue(dev);
-        ax25_listen_register((ax25_address *)dev->dev_addr, NULL);
+
         return 0;
 }