Re: [PATCH v2 for-rc 3/5] RDMA/hns: Remove enable rq inline in kernel and add compatibility handling

["xuhaoyue (A)" <xuhaoyue1@hisilicon.com>]

This bit is used to prevent compatibility issues in the old kernel. It is not for compatibility with userspace.
It should be a bugfix. I will separate this into a new bugfix patch.
I will change the name to __HNS_ROCE_CAP_FLAG_RQ_INLINE in V3.

On 2022/10/29 0:40:11, Jason Gunthorpe wrote:
> On Wed, Oct 26, 2022 at 05:50:52PM +0800, Haoyue Xu wrote:
>> From: Luoyouming <luoyouming@huawei.com>
>>
>> The rq inline makes some changes as follows, Firstly, it is only
>> used in user space. Secondly, it should notify hardware in QP RTR
>> status. Thirdly, Add compatibility processing between different
>> user space and kernel space. Change the HNS_ROCE_CAP_FLAG_RQ_INLINE
>> to a new bit to prevent old kernel spaces / spaced from enabling
>> rq inline.
>>
>> Signed-off-by: Luoyouming <luoyouming@huawei.com>
>> Signed-off-by: Haoyue Xu <xuhaoyue1@hisilicon.com>
>> ---
>>  drivers/infiniband/hw/hns/hns_roce_device.h |  6 +++--
>>  drivers/infiniband/hw/hns/hns_roce_hw_v2.c  | 28 +++++++++++++--------
>>  drivers/infiniband/hw/hns/hns_roce_main.c   |  5 ++++
>>  drivers/infiniband/hw/hns/hns_roce_qp.c     |  2 +-
>>  include/uapi/rdma/hns-abi.h                 |  2 ++
>>  5 files changed, 30 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
>> index f701cc86896b..9ce053fe737d 100644
>> --- a/drivers/infiniband/hw/hns/hns_roce_device.h
>> +++ b/drivers/infiniband/hw/hns/hns_roce_device.h
>> @@ -132,7 +132,8 @@ enum hns_roce_event {
>>  enum {
>>  	HNS_ROCE_CAP_FLAG_REREG_MR		= BIT(0),
>>  	HNS_ROCE_CAP_FLAG_ROCE_V1_V2		= BIT(1),
>> -	HNS_ROCE_CAP_FLAG_RQ_INLINE		= BIT(2),
>> +	/* discard this bit, reserved for compatibility */
>> +	HNS_ROCE_CAP_FLAG_DISCARD		= BIT(2),
> 
> If it is for compatability with userspace why is this enum not under
> include/uapi? Something has gone wrong here, please fix it.
> 
> Also, it is better to name this __HNS_ROCE_CAP_FLAG_RQ_INLINE to
> indicate it is not used instead of 'discard'
> 
> Jason
> .
>