Subject: Re: [PATCH v2 04/14] mailbox: mediatek: cmdq: clear task in channel before shutdown

From: Dennis-YC Hsieh <[email-masked]>
Date: Thu, 12 Dec 2019 09:13:41 +0800

Hi CK,

On Tue, 2019-12-10 at 10:49 +0800, CK Hu wrote:
> Hi, Dennis:
> 
> On Wed, 2019-11-27 at 09:58 +0800, Dennis YC Hsieh wrote:
> > Do success callback in channel when shutdown. For those task not finish,
> > callback with error code thus client has chance to cleanup or reset.
> > 
> > Signed-off-by: Dennis YC Hsieh <[email-masked]>
> > ---
> >  drivers/mailbox/mtk-cmdq-mailbox.c | 26 ++++++++++++++++++++++++++
> >  1 file changed, 26 insertions(+)
> > 
> > diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
> > index fd519b6f518b..c12a768d1175 100644
> > --- a/drivers/mailbox/mtk-cmdq-mailbox.c
> > +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
> > @@ -450,6 +450,32 @@ static int cmdq_mbox_startup(struct mbox_chan *chan)
> >  
> >  static void cmdq_mbox_shutdown(struct mbox_chan *chan)
> >  {
> > +	struct cmdq_thread *thread = (struct cmdq_thread *)chan->con_priv;
> > +	struct cmdq *cmdq = dev_get_drvdata(chan->mbox->dev);
> > +	struct cmdq_task *task, *tmp;
> > +	unsigned long flags;
> > +
> > +	spin_lock_irqsave(&thread->chan->lock, flags);
> > +	if (list_empty(&thread->task_busy_list))
> > +		goto done;
> > +
> > +	WARN_ON(cmdq_thread_suspend(cmdq, thread) < 0);
> > +
> > +	/* make sure executed tasks have success callback */
> > +	cmdq_thread_irq_handler(cmdq, thread);
> > +	if (list_empty(&thread->task_busy_list))
> > +		goto done;
> > +
> > +	list_for_each_entry_safe(task, tmp, &thread->task_busy_list,
> > +				 list_entry) {
> > +		cmdq_task_exec_done(task, -ECONNABORTED);
> > +		kfree(task);
> > +	}
> > +
> > +	cmdq_thread_disable(cmdq, thread);
> > +	clk_disable(cmdq->clock);
> > +done:
> 
> cmdq_thread_resume(thread);
> 
> Regards,
> CK
> 

Call resume here will cause violation. The thread->task_busy_list empty
means no task work in gce and thread state should already disable
without clock, which is what we want since client try to shut down this
mbox channel. So I think we don't need resume here.

Regards,
Dennis

> > +	spin_unlock_irqrestore(&thread->chan->lock, flags);
> >  }
> >  
> >  static const struct mbox_chan_ops cmdq_mbox_chan_ops = {
> 
> 

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