linux-kernel - Re: [PATCH] dmaengine: idxd: Set workqueue state to disabled before trying to re-enable

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Date:   Wed, 24 Aug 2022 13:29:03 -0700
From:   Dave Jiang <dave.jiang@...el.com>
To:     Jerry Snitselaar <jsnitsel@...hat.com>,
        linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>, Vinod Koul <vkoul@...nel.org>,
        dmaengine@...r.kernel.org
Subject: Re: [PATCH] dmaengine: idxd: Set workqueue state to disabled before
 trying to re-enable


On 8/24/2022 12:29 PM, Jerry Snitselaar wrote:
> For a software reset idxd_device_reinit() is called, which will walk
> the device workqueues to see which ones were enabled, and try to
> re-enable them. It keys off wq->state being iDXD_WQ_ENABLED, but the
> first thing idxd_enable_wq() will do is see that the state of the
> workqueue is enabled, and return 0 instead of attempting to issue
> a command to enable the workqueue.
>
> So once a workqueue is found that needs to be re-enabled,
> set the state to disabled prior to calling idxd_enable_wq().
> This would accurately reflect the state if the enable fails
> as well.
>
> Cc: Fenghua Yu <fenghua.yu@...el.com>
> Cc: Dave Jiang <dave.jiang@...el.com>
> Cc: Vinod Koul <vkoul@...nel.org>
> Cc: dmaengine@...r.kernel.org
> Fixes: bfe1d56091c1 ("dmaengine: idxd: Init and probe for Intel data accelerators")
> Signed-off-by: Jerry Snitselaar <jsnitsel@...hat.com>
> ---
>   drivers/dma/idxd/irq.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> index 743ead5ebc57..723eeb5328d6 100644
> --- a/drivers/dma/idxd/irq.c
> +++ b/drivers/dma/idxd/irq.c
> @@ -52,6 +52,7 @@ static void idxd_device_reinit(struct work_struct *work)
>   		struct idxd_wq *wq = idxd->wqs[i];
>   
>   		if (wq->state == IDXD_WQ_ENABLED) {
> +			wq->state = IDXD_WQ_DISABLED;
Might be better off to insert this line in idxd_wq_disable_cleanup(). I 
think that should put it in sane state.
>   			rc = idxd_wq_enable(wq);
>   			if (rc < 0) {
>   				dev_warn(dev, "Unable to re-enable wq %s\n",