The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1.   This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
  (..., NULL)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
        if (query->startup_sent < br->multicast_startup_query_count)
                query->startup_sent++;
 
-       rcu_assign_pointer(querier, NULL);
+       RCU_INIT_POINTER(querier, NULL);
        br_multicast_send_query(br, NULL, query);
        spin_unlock(&br->multicast_lock);
 }