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Subject: Re: [RESEND net-next 1/2] net: hns3: add support for PTP
To:     Richard Cochran <richardcochran@gmail.com>
CC:     <davem@davemloft.net>, <kuba@kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <salil.mehta@huawei.com>,
        <lipeng321@huawei.com>, <tanhuazhong@huawei.com>
References: <1622602664-20274-1-git-send-email-huangguangbin2@huawei.com>
 <1622602664-20274-2-git-send-email-huangguangbin2@huawei.com>
 <20210603131452.GA6216@hoboy.vegasvil.org>
From:   "huangguangbin (A)" <huangguangbin2@huawei.com>
Message-ID: <4b2247bc-605e-3aca-3bcb-c06477cd2f2e@huawei.com>
Date:   Sat, 5 Jun 2021 17:54:45 +0800
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On 2021/6/3 21:14, Richard Cochran wrote:
> 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.
> 
Thanks for review. Using spinlock in irq_handler looks heavy, what about
adding a new flag HCLGE_STATE_PTP_CLEANING_TX_HWTS for hclge_ptp_clean_tx_hwts()?
Function hclge_ptp_clean_tx_hwts() test and set this flag at the beginning
and clean it in the end. Do you think it is Ok?

Thanks,
Guangbin
.

>> +	/* 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
> .
>