[NET]: Save space for dst underflow message.

Save space for 'dst underflow' message.
Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@redhat.com>

include/net/dst.h

@@ -142,15 +142,14 @@ struct dst_entry * dst_clone(struct dst_entry * dst)
 	return dst;
 }
 
+extern const char dst_underflow_bug_msg[];
+
 static inline
 void dst_release(struct dst_entry * dst)
 {
 	if (dst) {
-		if (atomic_read(&dst->__refcnt) < 1) {
-			printk("BUG: dst underflow %d: %p\n",
-			       atomic_read(&dst->__refcnt),
-			       current_text_addr());
-		}
+		if (atomic_read(&dst->__refcnt) < 1)
+			printk(dst_underflow_bug_msg, dst, current_text_addr());
 		atomic_dec(&dst->__refcnt);
 	}
 }

net/core/dst.c

@@ -19,6 +19,8 @@
 
 #include <net/dst.h>
 
+const char dst_underflow_bug_msg[] = KERN_DEBUG "BUG: dst underflow %d: %p at %p\n";
+
 /* Locking strategy:
  * 1) Garbage collection state of dead destination cache
  *    entries is protected by dst_lock.
@@ -273,6 +275,7 @@ void __init dst_init(void)
 	register_netdevice_notifier(&dst_dev_notifier);
 }
 
+EXPORT_SYMBOL(dst_underflow_bug_msg);
 EXPORT_SYMBOL(__dst_free);
 EXPORT_SYMBOL(dst_alloc);
 EXPORT_SYMBOL(dst_destroy);