Commit 038366c5 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Tejun Heo

workqueue: make work_busy() test WORK_STRUCT_PENDING first

Currently, work_busy() first tests whether the work has a pool
associated with it and if not, considers it idle.  This works fine
even for delayed_work.work queued on timer, as __queue_delayed_work()
sets cwq on delayed_work.work - a queued delayed_work always has its
cwq and thus pool associated with it.

However, we're about to update delayed_work queueing and this won't
hold.  Update work_busy() such that it tests WORK_STRUCT_PENDING
before the associated pool.  This doesn't make any noticeable behavior
difference now.

With work_pending() test moved, the function read a lot better with
"if (!pool)" test flipped to positive.  Flip it.

While at it, lose the comment about now non-existent reentrant
workqueues.

tj: Reorganized the function and rewrote the description.
Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 6be19588
......@@ -3443,8 +3443,6 @@ EXPORT_SYMBOL_GPL(workqueue_congested);
* Test whether @work is currently pending or running. There is no
* synchronization around this function and the test result is
* unreliable and only useful as advisory hints or for debugging.
* Especially for reentrant wqs, the pending state might hide the
* running state.
*
* RETURNS:
* OR'd bitmask of WORK_BUSY_* bits.
......@@ -3455,17 +3453,15 @@ unsigned int work_busy(struct work_struct *work)
unsigned long flags;
unsigned int ret = 0;
if (!pool)
return 0;
spin_lock_irqsave(&pool->lock, flags);
if (work_pending(work))
ret |= WORK_BUSY_PENDING;
if (find_worker_executing_work(pool, work))
ret |= WORK_BUSY_RUNNING;
spin_unlock_irqrestore(&pool->lock, flags);
if (pool) {
spin_lock_irqsave(&pool->lock, flags);
if (find_worker_executing_work(pool, work))
ret |= WORK_BUSY_RUNNING;
spin_unlock_irqrestore(&pool->lock, flags);
}
return ret;
}
......
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