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

Leon Romanovsky
2024-07-08T07:33:19Z

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

>
> 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
> >>>>
> >>
>