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Commit a25909a4 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

lockdep: Add an in_workqueue_context() lockdep-based test function 



Some recent uses of RCU make use of workqueues.  In these uses, execution
within the context of a specific workqueue takes the place of the usual
RCU read-side primitives such as rcu_read_lock(), and flushing of workqueues
takes the place of the usual RCU grace-period primitives.  Checking for
correct use of rcu_dereference() in such cases requires a test of whether
the code is executing in the context of a particular workqueue.  This
commit adds an in_workqueue_context() function that provides this test.
This new function is only defined when lockdep is enabled, which allows
it to be used as the second argument of rcu_dereference_check().

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 71d1d5c7

include/linux/workqueue.h

+4 −0
Original line number Diff line number Diff line
@@ -297,4 +297,8 @@ static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) 
#else

long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);

#endif /* CONFIG_SMP */



#ifdef CONFIG_LOCKDEP

int in_workqueue_context(struct workqueue_struct *wq);

#endif

#endif

kernel/workqueue.c

+15 −0
Original line number Diff line number Diff line
@@ -68,6 +68,21 @@ struct workqueue_struct { 
#endif

};



#ifdef CONFIG_LOCKDEP

/**

 * in_workqueue_context() - in context of specified workqueue?

 * @wq: the workqueue of interest

 *

 * Checks lockdep state to see if the current task is executing from

 * within a workqueue item.  This function exists only if lockdep is

 * enabled.

 */

int in_workqueue_context(struct workqueue_struct *wq)

{

	return lock_is_held(&wq->lockdep_map);

}

#endif



#ifdef CONFIG_DEBUG_OBJECTS_WORK



static struct debug_obj_descr work_debug_descr;