On Wed, Jul 31, 2019 at 10:43:01AM +0800, oulijun wrote:
> 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?
I don't understand first part of your sentence, and "no" to second part.
Thanks
>
>
>
