Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bde23c68 authored by Heiko Carstens's avatar Heiko Carstens Committed by Paul E. McKenney
Browse files

rcu: Convert WARN_ON_ONCE() in rcu_lock_acquire() to lockdep 



The WARN_ON_ONCE() in rcu_lock_acquire() results in infinite recursion
on S390, and also doesn't print very much information.  Remove this.

Updated patch to add lockdep-RCU assertions to RCU's read-side primitives.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 7129d383

include/linux/rcupdate.h

+12 −2
Original line number Diff line number Diff line
@@ -248,13 +248,11 @@ static inline int rcu_is_cpu_idle(void) 


static inline void rcu_lock_acquire(struct lockdep_map *map)

{

	WARN_ON_ONCE(rcu_is_cpu_idle());

	lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_);

}



static inline void rcu_lock_release(struct lockdep_map *map)

{

	WARN_ON_ONCE(rcu_is_cpu_idle());

	lock_release(map, 1, _THIS_IP_);

}
@@ -699,6 +697,8 @@ static inline void rcu_read_lock(void) 
	__rcu_read_lock();

	__acquire(RCU);

	rcu_lock_acquire(&rcu_lock_map);

	rcu_lockdep_assert(!rcu_is_cpu_idle(),

			   "rcu_read_lock() used illegally while idle");

}



/*
@@ -718,6 +718,8 @@ static inline void rcu_read_lock(void) 
 */

static inline void rcu_read_unlock(void)

{

	rcu_lockdep_assert(!rcu_is_cpu_idle(),

			   "rcu_read_unlock() used illegally while idle");

	rcu_lock_release(&rcu_lock_map);

	__release(RCU);

	__rcu_read_unlock();
@@ -745,6 +747,8 @@ static inline void rcu_read_lock_bh(void) 
	local_bh_disable();

	__acquire(RCU_BH);

	rcu_lock_acquire(&rcu_bh_lock_map);

	rcu_lockdep_assert(!rcu_is_cpu_idle(),

			   "rcu_read_lock_bh() used illegally while idle");

}



/*
@@ -754,6 +758,8 @@ static inline void rcu_read_lock_bh(void) 
 */

static inline void rcu_read_unlock_bh(void)

{

	rcu_lockdep_assert(!rcu_is_cpu_idle(),

			   "rcu_read_unlock_bh() used illegally while idle");

	rcu_lock_release(&rcu_bh_lock_map);

	__release(RCU_BH);

	local_bh_enable();
@@ -777,6 +783,8 @@ static inline void rcu_read_lock_sched(void) 
	preempt_disable();

	__acquire(RCU_SCHED);

	rcu_lock_acquire(&rcu_sched_lock_map);

	rcu_lockdep_assert(!rcu_is_cpu_idle(),

			   "rcu_read_lock_sched() used illegally while idle");

}



/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
@@ -793,6 +801,8 @@ static inline notrace void rcu_read_lock_sched_notrace(void) 
 */

static inline void rcu_read_unlock_sched(void)

{

	rcu_lockdep_assert(!rcu_is_cpu_idle(),

			   "rcu_read_unlock_sched() used illegally while idle");

	rcu_lock_release(&rcu_sched_lock_map);

	__release(RCU_SCHED);

	preempt_enable();

include/linux/srcu.h

+4 −0
Original line number Diff line number Diff line
@@ -172,6 +172,8 @@ 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;

}
@@ -185,6 +187,8 @@ 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);

}