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authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-20 09:03:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-20 09:03:02 -0700
commitfa5312d9e87e7222c6c384c4e930dc149bc1178d (patch)
tree3a181e52c7ae863de566a6b30248a175742a8406 /kernel
parent9c688c114c4665ac8c6da05b2f6b987f4adc6dae (diff)
parent4d707b9f48e2c4aa94b96f1133813b73df71fb55 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: change cancel_work_sync() to clear work->data workqueue: warn about flush_scheduled_work()
Diffstat (limited to 'kernel')
-rw-r--r--kernel/workqueue.c36
1 files changed, 35 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 5bfb213984b2..77dabbf64b8f 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -229,6 +229,16 @@ static inline void set_wq_data(struct work_struct *work,
atomic_long_set(&work->data, new);
}
+/*
+ * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued.
+ */
+static inline void clear_wq_data(struct work_struct *work)
+{
+ unsigned long flags = *work_data_bits(work) &
+ (1UL << WORK_STRUCT_STATIC);
+ atomic_long_set(&work->data, flags);
+}
+
static inline
struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
{
@@ -671,7 +681,7 @@ static int __cancel_work_timer(struct work_struct *work,
wait_on_work(work);
} while (unlikely(ret < 0));
- work_clear_pending(work);
+ clear_wq_data(work);
return ret;
}
@@ -845,6 +855,30 @@ int schedule_on_each_cpu(work_func_t func)
return 0;
}
+/**
+ * flush_scheduled_work - ensure that any scheduled work has run to completion.
+ *
+ * Forces execution of the kernel-global workqueue and blocks until its
+ * completion.
+ *
+ * Think twice before calling this function! It's very easy to get into
+ * trouble if you don't take great care. Either of the following situations
+ * will lead to deadlock:
+ *
+ * One of the work items currently on the workqueue needs to acquire
+ * a lock held by your code or its caller.
+ *
+ * Your code is running in the context of a work routine.
+ *
+ * They will be detected by lockdep when they occur, but the first might not
+ * occur very often. It depends on what work items are on the workqueue and
+ * what locks they need, which you have no control over.
+ *
+ * In most situations flushing the entire workqueue is overkill; you merely
+ * need to know that a particular work item isn't queued and isn't running.
+ * In such cases you should use cancel_delayed_work_sync() or
+ * cancel_work_sync() instead.
+ */
void flush_scheduled_work(void)
{
flush_workqueue(keventd_wq);