Commit 29b1cb41 authored Jul 22, 2014 by Lai Jiangshan Committed by Tejun Heo Jul 22, 2014

workqueue: remove the stale comment in pwq_unbound_release_workfn()



In 75ccf595 ("workqueue: prepare flush_workqueue() for dynamic
creation and destrucion of unbound pool_workqueues"), a comment
about the synchronization for the pwq in pwq_unbound_release_workfn()
was added. The comment claimed the flush_mutex wasn't strictly
necessary, it was correct in that time, due to the pwq was protected
by workqueue_lock.

But it is incorrect now since the wq->flush_mutex was renamed to
wq->mutex and workqueue_lock was removed, the wq->mutex is strictly
needed. But the comment was miss-updated when the synchronization
was changed.

This patch removes the incorrect comments and doesn't add any new
comment to explain why wq->mutex is needed here, which is definitely
obvious and wq->pwqs_node has "WQ" notation in its definition which is
better comment.

The old commit mentioned above also introduced a comment in link_pwq()
about the synchronization. This comment is also removed in this patch
since the whole link_pwq() is proteced by wq->mutex.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent 13b1d625

kernel/workqueue.c

+1 −9

Original line number	Diff line number	Diff line
		@@ -3530,11 +3530,6 @@ static void pwq_unbound_release_workfn(struct work_struct *work)
		if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
		return;

		/*
		* Unlink @pwq. Synchronization against wq->mutex isn't strictly
		* necessary on release but do it anyway. It's easier to verify
		* and consistent with the linking path.
		*/
		mutex_lock(&wq->mutex);
		list_del_rcu(&pwq->pwqs_node);
		is_last = list_empty(&wq->pwqs);
		@@ -3631,10 +3626,7 @@ static void link_pwq(struct pool_workqueue *pwq)
		if (!list_empty(&pwq->pwqs_node))
		return;

		/*
		* Set the matching work_color. This is synchronized with
		* wq->mutex to avoid confusing flush_workqueue().
		*/
		/* set the matching work_color */
		pwq->work_color = wq->work_color;

		/* sync max_active to the current setting */

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