Commit 32d99593 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Add lockdep_assert_in_rcu_read_lock() and friends 



There is no direct RCU counterpart to lockdep_assert_irqs_disabled()
and friends.  Although it is possible to construct them, it would
be more convenient to have the following lockdep assertions:

lockdep_assert_in_rcu_read_lock()
lockdep_assert_in_rcu_read_lock_bh()
lockdep_assert_in_rcu_read_lock_sched()
lockdep_assert_in_rcu_reader()

This commit therefore creates them.

Reported-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 1613e604

include/linux/rcupdate.h

+60 −0
Original line number Diff line number Diff line
@@ -421,11 +421,71 @@ static inline void rcu_preempt_sleep_check(void) { } 
				 "Illegal context switch in RCU-sched read-side critical section"); \

	} while (0)



// See RCU_LOCKDEP_WARN() for an explanation of the double call to

// debug_lockdep_rcu_enabled().

static inline bool lockdep_assert_rcu_helper(bool c)

{

	return debug_lockdep_rcu_enabled() &&

	       (c || !rcu_is_watching() || !rcu_lockdep_current_cpu_online()) &&

	       debug_lockdep_rcu_enabled();

}



/**

 * lockdep_assert_in_rcu_read_lock - WARN if not protected by rcu_read_lock()

 *

 * Splats if lockdep is enabled and there is no rcu_read_lock() in effect.

 */

#define lockdep_assert_in_rcu_read_lock() \

	WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_lock_map)))



/**

 * lockdep_assert_in_rcu_read_lock_bh - WARN if not protected by rcu_read_lock_bh()

 *

 * Splats if lockdep is enabled and there is no rcu_read_lock_bh() in effect.

 * Note that local_bh_disable() and friends do not suffice here, instead an

 * actual rcu_read_lock_bh() is required.

 */

#define lockdep_assert_in_rcu_read_lock_bh() \

	WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_bh_lock_map)))



/**

 * lockdep_assert_in_rcu_read_lock_sched - WARN if not protected by rcu_read_lock_sched()

 *

 * Splats if lockdep is enabled and there is no rcu_read_lock_sched()

 * in effect.  Note that preempt_disable() and friends do not suffice here,

 * instead an actual rcu_read_lock_sched() is required.

 */

#define lockdep_assert_in_rcu_read_lock_sched() \

	WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_sched_lock_map)))



/**

 * lockdep_assert_in_rcu_reader - WARN if not within some type of RCU reader

 *

 * Splats if lockdep is enabled and there is no RCU reader of any

 * type in effect.  Note that regions of code protected by things like

 * preempt_disable, local_bh_disable(), and local_irq_disable() all qualify

 * as RCU readers.

 *

 * Note that this will never trigger in PREEMPT_NONE or PREEMPT_VOLUNTARY

 * kernels that are not also built with PREEMPT_COUNT.  But if you have

 * lockdep enabled, you might as well also enable PREEMPT_COUNT.

 */

#define lockdep_assert_in_rcu_reader()								\

	WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_lock_map) &&			\

					       !lock_is_held(&rcu_bh_lock_map) &&		\

					       !lock_is_held(&rcu_sched_lock_map) &&		\

					       preemptible()))



#else /* #ifdef CONFIG_PROVE_RCU */



#define RCU_LOCKDEP_WARN(c, s) do { } while (0 && (c))

#define rcu_sleep_check() do { } while (0)



#define lockdep_assert_in_rcu_read_lock() do { } while (0)

#define lockdep_assert_in_rcu_read_lock_bh() do { } while (0)

#define lockdep_assert_in_rcu_read_lock_sched() do { } while (0)

#define lockdep_assert_in_rcu_reader() do { } while (0)



#endif /* #else #ifdef CONFIG_PROVE_RCU */



/*