Re: [B.A.T.M.A.N.] [PATCH] batman-adv: compat: fix null pointer exception for kernels < 3.9

[Antonio Quartulli <antonio@meshcoding.com>]

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On 16/02/14 13:01, Linus Lüssing wrote:
> @@ -371,12 +372,13 @@ static int __batadv_interface_tx(struct sk_buff *skb, \
>  
>  #ifndef netdev_master_upper_dev_get_rcu
>  #define netdev_master_upper_dev_get_rcu(dev) \
> -	NULL; \
> +	upper; \
>  	if (dev->priv_flags & IFF_BRIDGE_PORT) { \
>  		rcu_read_unlock(); \
>  		dev_hold(dev); \
>  		return dev; \
> -	}
> +	} else \
> +		dev = NULL;
>  

Following your patch the code in multicast.c will become:

172         do {
173                 upper = upper;
			if (dev->priv_flags & IFF_BRIDGE_PORT) {
				rcu_read_unlock();
				dev_hold(dev);
				return dev;
			} else
				dev = NULL;
174         } while (upper && !(upper->priv_flags & IFF_EBRIDGE));

am I wrong or this is going to break the while? I think there is a
missing '}'.


What about a simplified version like this:

 #define netdev_master_upper_dev_get_rcu(dev) \
-	NULL; \
-	if (dev->priv_flags & IFF_BRIDGE_PORT) { \
+	({if (dev->priv_flags & IFF_BRIDGE_PORT) { \
 		rcu_read_unlock(); \
 		dev_hold(dev); \
 		return dev; \
-	}
+	}\
+	NULL;})


Cheers,

-- 
Antonio Quartulli


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