Use WARN rather than printk followed by WARN_ON(1), for conciseness.
A simplified version of the semantic patch that makes this transformation
is as follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
expression list es;
@@
-printk(
+WARN(1,
  es);
-WARN_ON(1);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
        /* Synchronize with scheduled polling */
        napi_disable(&mal->napi);
 
-       if (!list_empty(&mal->list)) {
+       if (!list_empty(&mal->list))
                /* This is *very* bad */
-               printk(KERN_EMERG
+               WARN(1, KERN_EMERG
                       "mal%d: commac list is not empty on remove!\n",
                       mal->index);
-               WARN_ON(1);
-       }
 
        dev_set_drvdata(&ofdev->dev, NULL);