void fastcall call_rcu_bh (struct rcu_head * head, void (*func) struct rcu_head *rcu);
The update function will be invoked some time after a full grace period elapses, in other words after all currently executing RCU read-side critical sections have completed. call_rcu_bh assumes that the read-side critical sections end on completion of a softirq handler. This means that read-side critical sections in process context must not be interrupted by softirqs. This interface is to be used when most of the read-side critical sections are in softirq context. RCU read-side critical sections are delimited by rcu_read_lock and rcu_read_unlock, * if in interrupt context or rcu_read_lock_bh and rcu_read_unlock_bh, if in process context. These may be nested.