Re: [PATCH for-rc 2/9] RDMA/hns: Fix a long wait for cmdq event during reset

[Junxian Huang <huangjunxian6@hisilicon.com>]

On 2024/7/8 15:33, Leon Romanovsky wrote:
> On Mon, Jul 08, 2024 at 02:50:50PM +0800, Junxian Huang wrote:
>>
>>
>> On 2024/7/8 13:38, Leon Romanovsky wrote:
>>> On Mon, Jul 08, 2024 at 10:29:54AM +0800, Junxian Huang wrote:
>>>>
>>>>
>>>> On 2024/7/7 16:30, Leon Romanovsky wrote:
>>>>> On Fri, Jul 05, 2024 at 04:59:30PM +0800, Junxian Huang wrote:
>>>>>> From: wenglianfa <wenglianfa@huawei.com>
>>>>>>
>>>>>> During reset, cmdq events won't be reported, leading to a long and
>>>>>> unnecessary wait. Notify all the cmdqs to stop waiting at the beginning
>>>>>> of reset.
>>>>>>
>>>>>> Fixes: 9a4435375cd1 ("IB/hns: Add driver files for hns RoCE driver")
>>>>>> Signed-off-by: wenglianfa <wenglianfa@huawei.com>
>>>>>> Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
>>>>>> ---
>>>>>>  drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 18 ++++++++++++++++++
>>>>>>  1 file changed, 18 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>>>>>> index a5d746a5cc68..ff135df1a761 100644
>>>>>> --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>>>>>> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>>>>>> @@ -6977,6 +6977,21 @@ static void hns_roce_hw_v2_uninit_instance(struct hnae3_handle *handle,
>>>>>>  
>>>>>>  	handle->rinfo.instance_state = HNS_ROCE_STATE_NON_INIT;
>>>>>>  }
>>>>>> +
>>>>>> +static void hns_roce_v2_reset_notify_cmd(struct hns_roce_dev *hr_dev)
>>>>>> +{
>>>>>> +	struct hns_roce_cmdq *hr_cmd = &hr_dev->cmd;
>>>>>> +	int i;
>>>>>> +
>>>>>> +	if (!hr_dev->cmd_mod)
>>>>>
>>>>> What prevents cmd_mod from being changed?
>>>>>
>>>>
>>>> It's set when the device is being initialized, and won't be changed after that.
>>>
>>> This is exactly the point, you are assuming that the device is already
>>> ininitialized or not initialized at all. What prevents hns_roce_v2_reset_notify_cmd()
>>> from being called in the middle of initialization?
>>>
>>> Thanks
>>>
>>
>> This is ensured by hns3 NIC driver.
>>
>> Initialization and reset of hns RoCE are both called by hns3. It will check the state
>> of RoCE device (see line 3798), and notify RoCE device to reset (hns_roce_v2_reset_notify_cmd()
>> is called) only if the RoCE device has been already initialized:
> 
> So why do you have "if (!hr_dev->cmd_mod)" check in the code?
> 
> Thanks
> 

cmd_mod indicates the mode of cmdq (0: poll mode, 1: event mode).
This patch only affects event mode because HW won't report events during reset.

Junxian

>>
>>  3791 static int hclge_notify_roce_client(struct hclge_dev *hdev,
>>  3792                                     enum hnae3_reset_notify_type type)
>>  3793 {
>>  3794         struct hnae3_handle *handle = &hdev->vport[0].roce;
>>  3795         struct hnae3_client *client = hdev->roce_client;
>>  3796         int ret;
>>  3797
>>  3798         if (!test_bit(HCLGE_STATE_ROCE_REGISTERED, &hdev->state) || !client)
>>  3799                 return 0;
>>  3800
>>  3801         if (!client->ops->reset_notify)
>>  3802                 return -EOPNOTSUPP;
>>  3803
>>  3804         ret = client->ops->reset_notify(handle, type);
>>  3805         if (ret)
>>  3806                 dev_err(&hdev->pdev->dev, "notify roce client failed %d(%d)",
>>  3807                         type, ret);
>>  3808
>>  3809         return ret;
>>  3810 }
>>
>> And the bit is set (see line 11246) after the initialization has been done (line 11242):
>>
>> 11224 static int hclge_init_roce_client_instance(struct hnae3_ae_dev *ae_dev,
>> 11225                                            struct hclge_vport *vport)
>> 11226 {
>> 11227         struct hclge_dev *hdev = ae_dev->priv;
>> 11228         struct hnae3_client *client;
>> 11229         int rst_cnt;
>> 11230         int ret;
>> 11231
>> 11232         if (!hnae3_dev_roce_supported(hdev) || !hdev->roce_client ||
>> 11233             !hdev->nic_client)
>> 11234                 return 0;
>> 11235
>> 11236         client = hdev->roce_client;
>> 11237         ret = hclge_init_roce_base_info(vport);
>> 11238         if (ret)
>> 11239                 return ret;
>> 11240
>> 11241         rst_cnt = hdev->rst_stats.reset_cnt;
>> 11242         ret = client->ops->init_instance(&vport->roce);
>> 11243         if (ret)
>> 11244                 return ret;
>> 11245
>> 11246         set_bit(HCLGE_STATE_ROCE_REGISTERED, &hdev->state);
>> 11247         if (test_bit(HCLGE_STATE_RST_HANDLING, &hdev->state) ||
>> 11248             rst_cnt != hdev->rst_stats.reset_cnt) {
>> 11249                 ret = -EBUSY;
>> 11250                 goto init_roce_err;
>> 11251         }
>>
>> Junxian
>>
>>>>
>>>> Junxian
>>>>
>>>>>> +		return;
>>>>>> +
>>>>>> +	for (i = 0; i < hr_cmd->max_cmds; i++) {
>>>>>> +		hr_cmd->context[i].result = -EBUSY;
>>>>>> +		complete(&hr_cmd->context[i].done);
>>>>>> +	}
>>>>>> +}
>>>>>> +
>>>>>>  static int hns_roce_hw_v2_reset_notify_down(struct hnae3_handle *handle)
>>>>>>  {
>>>>>>  	struct hns_roce_dev *hr_dev;
>>>>>> @@ -6997,6 +7012,9 @@ static int hns_roce_hw_v2_reset_notify_down(struct hnae3_handle *handle)
>>>>>>  	hr_dev->dis_db = true;
>>>>>>  	hr_dev->state = HNS_ROCE_DEVICE_STATE_RST_DOWN;
>>>>>>  
>>>>>> +	/* Complete the CMDQ event in advance during the reset. */
>>>>>> +	hns_roce_v2_reset_notify_cmd(hr_dev);
>>>>>> +
>>>>>>  	return 0;
>>>>>>  }
>>>>>>  
>>>>>> -- 
>>>>>> 2.33.0
>>>>>>
>>>>
>>