Re: [PATCH 1/2] RDMA/uverbs: Don't set rcq if qp_type is IB_QPT_XRC_INI

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2021/1/13 4:09, Jason Gunthorpe wrote:
> On Wed, Dec 16, 2020 at 03:17:54PM +0800, Xiao Yang wrote:
>> INI QP doesn't require receive CQ.
>>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>>   drivers/infiniband/core/uverbs_cmd.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
>> index 418d133a8fb0..d8bc8ea3ad1e 100644
>> +++ b/drivers/infiniband/core/uverbs_cmd.c
>> @@ -1345,7 +1345,7 @@ static int create_qp(struct uverbs_attr_bundle *attrs,
>>   		if (has_sq)
>>   			scq = uobj_get_obj_read(cq, UVERBS_OBJECT_CQ,
>>   						cmd->send_cq_handle, attrs);
>> -		if (!ind_tbl)
>> +		if (!ind_tbl&&  cmd->qp_type != IB_QPT_XRC_INI)
>>   			rcq = rcq ?: scq;
> Hmm, this does make it consistent with the UVERBS_METHOD_QP_CREATE
> flow which does set attr.recv_cq to NULL if the user didn't specify one.
>
> However this has been like this since the beginning - what are you
> doing that this detail matters?
Hi Jason,

Thanks for your comment.
1) I didn't get any issue for now.
2) I think it is not meaningful to set rcq for XRC INITIATOR QP, current 
code has ignores rcq as below:
-------------------------------------------------
static int create_qp(struct uverbs_attr_bundle *attrs,
                     struct ib_uverbs_ex_create_qp *cmd)
...
                 if (cmd->qp_type == IB_QPT_XRC_INI) {
                         cmd->max_recv_wr = 0;
                         cmd->max_recv_sge = 0;
...
-------------------------------------------------

By the way, I have a question:
Why do we need two kinds of uverbs API?(a: read & write, b: ioctl)

Best Regards,
Xiao Yang
> Jason
>
>
> .
>