在 2019/7/30 21:40, Leon Romanovsky 写道:
> On Tue, Jul 30, 2019 at 04:56:47PM +0800, Lijun Ou wrote:
>> From: Lang Cheng <chenglang@xxxxxxxxxx>
>>
>> For hns_roce_v2_query_qp and hns_roce_v2_modify_qp,
>> we can use stack memory to create qp context data.
>> Make the code simpler.
>>
>> Signed-off-by: Lang Cheng <chenglang@xxxxxxxxxx>
>> ---
>> drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 64 +++++++++++++-----------------
>> 1 file changed, 27 insertions(+), 37 deletions(-)
>>
>> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> index 1186e34..07ddfae 100644
>> --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> @@ -4288,22 +4288,19 @@ static int hns_roce_v2_modify_qp(struct ib_qp *ibqp,
>> {
>> struct hns_roce_dev *hr_dev = to_hr_dev(ibqp->device);
>> struct hns_roce_qp *hr_qp = to_hr_qp(ibqp);
>> - struct hns_roce_v2_qp_context *context;
>> - struct hns_roce_v2_qp_context *qpc_mask;
>> + struct hns_roce_v2_qp_context ctx[2];
>> + struct hns_roce_v2_qp_context *context = ctx;
>> + struct hns_roce_v2_qp_context *qpc_mask = ctx + 1;
>> struct device *dev = hr_dev->dev;
>> int ret;
>>
>> - context = kcalloc(2, sizeof(*context), GFP_ATOMIC);
>> - if (!context)
>> - return -ENOMEM;
>> -
>> - qpc_mask = context + 1;
>> /*
>> * In v2 engine, software pass context and context mask to hardware
>> * when modifying qp. If software need modify some fields in context,
>> * we should set all bits of the relevant fields in context mask to
>> * 0 at the same time, else set them to 0x1.
>> */
>> + memset(context, 0, sizeof(*context));
> "struct hns_roce_v2_qp_context ctx[2] = {};" will do the trick.
>
> Thanks
>
> .
In this case, the mask is actually writen twice. if you do this, will it bring extra overhead when modify qp?
