Re: [PATCH for-next 1/2] RDMA/hns: Support query information of functions from FW

[liweihang <liweihang@huawei.com>]

On 2021/3/24 9:55, liweihang wrote:
> On 2021/3/24 3:56, Jason Gunthorpe wrote:
>> On Fri, Mar 12, 2021 at 05:48:26PM +0800, Weihang Li wrote:
>>
>>> +static int hns_roce_query_func_info(struct hns_roce_dev *hr_dev)
>>> +{
>>> +	struct hns_roce_pf_func_info *resp;
>>> +	struct hns_roce_cmq_desc desc;
>>> +	int ret;
>>> +
>>> +	if (hr_dev->pci_dev->revision < PCI_REVISION_ID_HIP09)
>>> +		return 0;
>>> +
>>> +	hns_roce_cmq_setup_basic_desc(&desc, HNS_ROCE_OPC_QUERY_FUNC_INFO,
>>> +				      true);
>>> +	ret = hns_roce_cmq_send(hr_dev, &desc, 1);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	resp = (struct hns_roce_pf_func_info *)desc.data;
>>
>> WTF is this cast?
>>
>> struct hns_roce_cmq_desc {
>>         __le16 opcode;
>>         __le16 flag;
>>         __le16 retval;
>>         __le16 rsv;
>>         __le32 data[6];
>> };
>>
>> Casting __le32 to a pointer is wrong
>>
>> Jason
>>
> 
> Hi Jason
> 
> desc.data is the address of array 'data[6]', it is got from the firmware, we
> cast it to 'struct hns_roce_pf_func_info *' to parse its contents. I think this
> is a cast from '__le32 *' to 'struct hns_roce_pf_func_info *'.
> 
> Thanks
> Weihang
> 
> 

Jason, do you mean the current code is not written correctly? Do you have any
suggestions for achieving our purpose?

Weihang