From a25909a4d4a29e272f953e12595bf2f04a292dbd Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 13 May 2010 12:32:28 -0700 Subject: 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: Paul E. McKenney --- kernel/workqueue.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'kernel/workqueue.c') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 327d2deb4451..59fef1531dd2 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -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; -- cgit v1.2.2