netdev - Re: [RESEND net-next 1/2] net: hns3: add support for PTP

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Message-ID: <20210603131452.GA6216@hoboy.vegasvil.org>
Date:   Thu, 3 Jun 2021 06:14:52 -0700
From:   Richard Cochran <richardcochran@...il.com>
To:     Guangbin Huang <huangguangbin2@...wei.com>
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, salil.mehta@...wei.com,
        lipeng321@...wei.com, tanhuazhong@...wei.com
Subject: Re: [RESEND net-next 1/2] net: hns3: add support for PTP

On Wed, Jun 02, 2021 at 10:57:43AM +0800, Guangbin Huang wrote:

> @@ -4342,12 +4352,34 @@ static void hclge_periodic_service_task(struct hclge_dev *hdev)
>  	hclge_task_schedule(hdev, delta);
>  }
>  
> +static void hclge_ptp_service_task(struct hclge_dev *hdev)
> +{
> +	if (!test_bit(HCLGE_STATE_PTP_EN, &hdev->state) ||
> +	    !test_bit(HCLGE_STATE_PTP_TX_HANDLING, &hdev->state) ||
> +	    !time_is_before_jiffies(hdev->ptp->tx_start + HZ))
> +		return;
> +
> +	/* to prevent concurrence with the irq handler, disable vector0
> +	 * before handling ptp service task.
> +	 */
> +	disable_irq(hdev->misc_vector.vector_irq);

This won't work.  After all, the ISR thread might already be running.
Use a proper spinlock instead.

> +	/* check HCLGE_STATE_PTP_TX_HANDLING here again, since the irq
> +	 * handler may handle it just before disable_irq().
> +	 */
> +	if (test_bit(HCLGE_STATE_PTP_TX_HANDLING, &hdev->state))
> +		hclge_ptp_clean_tx_hwts(hdev);
> +
> +	enable_irq(hdev->misc_vector.vector_irq);
> +}

Thanks,
Richard