Re: [PATCH rdma-next 4/5] RDMA/hns: Add reset process for RoCE in hip08

From: Wei Hu (Xavier)
Date: Fri May 18 2018 - 02:26:56 EST




On 2018/5/18 12:15, Jason Gunthorpe wrote:
> On Fri, May 18, 2018 at 11:28:11AM +0800, Wei Hu (Xavier) wrote:
>>
>> On 2018/5/17 23:14, Jason Gunthorpe wrote:
>>> On Thu, May 17, 2018 at 04:02:52PM +0800, Wei Hu (Xavier) wrote:
>>>> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>>>> index 86ef15f..e1c44a6 100644
>>>> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>>>> @@ -774,6 +774,9 @@ static int hns_roce_cmq_send(struct hns_roce_dev *hr_dev,
>>>> int ret = 0;
>>>> int ntc;
>>>>
>>>> + if (hr_dev->is_reset)
>>>> + return 0;
>>>> +
>>>> spin_lock_bh(&csq->lock);
>>>>
>>>> if (num > hns_roce_cmq_space(csq)) {
>>>> @@ -4790,6 +4793,7 @@ static int hns_roce_hw_v2_init_instance(struct hnae3_handle *handle)
>>>> return 0;
>>>>
>>>> error_failed_get_cfg:
>>>> + handle->priv = NULL;
>>>> kfree(hr_dev->priv);
>>>>
>>>> error_failed_kzalloc:
>>>> @@ -4803,14 +4807,70 @@ static void hns_roce_hw_v2_uninit_instance(struct hnae3_handle *handle,
>>>> {
>>>> struct hns_roce_dev *hr_dev = (struct hns_roce_dev *)handle->priv;
>>>>
>>>> + if (!hr_dev)
>>>> + return;
>>>> +
>>>> hns_roce_exit(hr_dev);
>>>> + handle->priv = NULL;
>>>> kfree(hr_dev->priv);
>>>> ib_dealloc_device(&hr_dev->ib_dev);
>>>> }
>>> Why are these hunks here? If init fails then uninit should not be
>>> called, so why meddle with priv?
>> In hns_roce_hw_v2_init_instance function, we evaluate handle->priv with
>> hr_dev,
>> We want clear the value in hns_roce_hw_v2_uninit_instance function.
>> So we can ensure no problem in RoCE driver.
> What problem could happen?
>
> I keep removing unnecessary sets to null and checks of null, so please
> don't add them if they cannot happen.
>
> Eg uninit should never be called with a null priv, that is a serious
> logic mis-design someplace if it happens.
>
> Jason
NIC driver call the registered reset_notify() function to finish the
part of RoCE reset process.
In RoCE driver, when hnae3_reset_notify_type is HNAE3_UNINIT_CLIENT,
we call hns_roce_hw_v2_uninit_instance(handle, false) to release the
resources.
when hnae3_reset_notify_type is HNAE3_INIT_CLIENT, we call
hns_roce_hw_v2_init_instance.
if hns_roce_hw_v2_init_instance failed, we should ensure no problem in
the other callback
function registered by RoCE driver.

The related RoCE driver:
static int hns_roce_hw_v2_reset_notify_uninit(struct hnae3_handle *handle)
{
msleep(100);
hns_roce_hw_v2_uninit_instance(handle, false);
return 0;
}

static int hns_roce_hw_v2_reset_notify(struct hnae3_handle *handle,
enum hnae3_reset_notify_type type)
{
int ret = 0;

switch (type) {
case HNAE3_DOWN_CLIENT:
ret = hns_roce_hw_v2_reset_notify_down(handle);
break;
case HNAE3_INIT_CLIENT:
ret = hns_roce_hw_v2_init_instance(handle);
break;
case HNAE3_UNINIT_CLIENT:
ret = hns_roce_hw_v2_reset_notify_uninit(handle);
break;
default:
break;
}

return ret;
}

The related NIC driver:

static int hclge_notify_roce_client(struct hclge_dev *hdev,
enum hnae3_reset_notify_type type)
{
struct hnae3_client *client = hdev->roce_client;
struct hnae3_handle *handle;
int ret = 0;
u16 i;

if (!client)
return 0;

if (!client->ops->reset_notify)
return -EOPNOTSUPP;

for (i = 0; i < hdev->num_vmdq_vport + 1; i++) {
handle = &hdev->vport[i].roce;
ret = client->ops->reset_notify(handle, type);
if (ret) {
dev_err(&hdev->pdev->dev,
"notify roce client failed %d", ret);
return ret;
}
}

return ret;
}

static void hclge_reset(struct hclge_dev *hdev)
{
struct hnae3_handle *handle;

/* perform reset of the stack & ae device for a client */
handle = &hdev->vport[0].nic;

hclge_notify_roce_client(hdev, HNAE3_DOWN_CLIENT);
hclge_notify_roce_client(hdev, HNAE3_UNINIT_CLIENT);

rtnl_lock();
hclge_notify_client(hdev, HNAE3_DOWN_CLIENT);

if (!hclge_reset_wait(hdev)) {
hclge_notify_client(hdev, HNAE3_UNINIT_CLIENT);
hclge_reset_ae_dev(hdev->ae_dev);
hclge_notify_client(hdev, HNAE3_INIT_CLIENT);

hclge_clear_reset_cause(hdev);
} else {
/* schedule again to check pending resets later */
set_bit(hdev->reset_type, &hdev->reset_pending);
hclge_reset_task_schedule(hdev);
}

hclge_notify_client(hdev, HNAE3_UP_CLIENT);
handle->last_reset_time = jiffies;
rtnl_unlock();

hclge_notify_roce_client(hdev, HNAE3_INIT_CLIENT);
hclge_notify_roce_client(hdev, HNAE3_UP_CLIENT);
}

Thanks, Jason

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