diff options
author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-05-13 12:32:28 -0700 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-06-14 16:37:26 -0700 |
commit | a25909a4d4a29e272f953e12595bf2f04a292dbd (patch) | |
tree | 86b54bc29aa126eff797b98728133ea960f8bd01 | |
parent | 71d1d5c722db9ae3b3f9c08ef7ddcd7759fbb1e0 (diff) |
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 <paulmck@linux.vnet.ibm.com>
-rw-r--r-- | include/linux/workqueue.h | 4 | ||||
-rw-r--r-- | kernel/workqueue.c | 15 |
2 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 9466e860d8c..d0f7c817849 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -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 diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 327d2deb445..59fef1531dd 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; |