static DEFINE_RWLOCK(queue_handler_lock);
+/* return EBUSY when somebody else is registered, return EEXIST if the
+ * same handler is registered, return 0 in case of success. */
int nf_register_queue_handler(int pf, struct nf_queue_handler *qh)
{
int ret;
return -EINVAL;
write_lock_bh(&queue_handler_lock);
- if (queue_handler[pf])
+ if (queue_handler[pf] == qh)
+ ret = -EEXIST;
+ else if (queue_handler[pf])
ret = -EBUSY;
else {
queue_handler[pf] = qh;