diff options
Diffstat (limited to 'include/linux/srcu.h')
| -rw-r--r-- | include/linux/srcu.h | 26 | 
1 files changed, 3 insertions, 23 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 6eb691b0835..04f4121a23a 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -151,30 +151,14 @@ void srcu_barrier(struct srcu_struct *sp);   * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot   * and while lockdep is disabled.   * - * Note that if the CPU is in the idle loop from an RCU point of view - * (ie: that we are in the section between rcu_idle_enter() and - * rcu_idle_exit()) then srcu_read_lock_held() returns false even if - * the CPU did an srcu_read_lock().  The reason for this is that RCU - * ignores CPUs that are in such a section, considering these as in - * extended quiescent state, so such a CPU is effectively never in an - * RCU read-side critical section regardless of what RCU primitives it - * invokes.  This state of affairs is required --- we need to keep an - * RCU-free window in idle where the CPU may possibly enter into low - * power mode. This way we can notice an extended quiescent state to - * other CPUs that started a grace period. Otherwise we would delay any - * grace period as long as we run in the idle task. - * - * Similarly, we avoid claiming an SRCU read lock held if the current - * CPU is offline. + * Note that SRCU is based on its own statemachine and it doesn't + * relies on normal RCU, it can be called from the CPU which + * is in the idle loop from an RCU point of view or offline.   */  static inline int srcu_read_lock_held(struct srcu_struct *sp)  {  	if (!debug_lockdep_rcu_enabled())  		return 1; -	if (rcu_is_cpu_idle()) -		return 0; -	if (!rcu_lockdep_current_cpu_online()) -		return 0;  	return lock_is_held(&sp->dep_map);  } @@ -236,8 +220,6 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)  	int retval = __srcu_read_lock(sp);  	rcu_lock_acquire(&(sp)->dep_map); -	rcu_lockdep_assert(!rcu_is_cpu_idle(), -			   "srcu_read_lock() used illegally while idle");  	return retval;  } @@ -251,8 +233,6 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)  static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)  	__releases(sp)  { -	rcu_lockdep_assert(!rcu_is_cpu_idle(), -			   "srcu_read_unlock() used illegally while idle");  	rcu_lock_release(&(sp)->dep_map);  	__srcu_read_unlock(sp, idx);  }  |