Jason Gunthorpe <jgg@xxxxxxxxxx> 于2021年6月18日周五 下午8:49写道：
>
> On Fri, Jun 18, 2021 at 06:05:58PM +0800, Weihang Li wrote:
> > Fix complains from sparse about "dubious: x & !y" when calling
> > hr_reg_write(ctx, field, !!val) by using "val ? 1 : 0" instead of "!!val".
> >
> > Fixes: dc504774408b ("RDMA/hns: Use new interface to set MPT related fields")
> > Fixes: 495c24808ce7 ("RDMA/hns: Add XRC subtype in QPC and XRC type in SRQC")
> > Fixes: 782832f25404 ("RDMA/hns: Simplify the function config_eqc()")
> > Signed-off-by: Weihang Li <liweihang@xxxxxxxxxx>
> > ---
> > drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 14 +++++++-------
> > 1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> > index fbc45b9..6452ccc 100644
> > --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> > +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> > @@ -3013,15 +3013,15 @@ static int hns_roce_v2_write_mtpt(struct hns_roce_dev *hr_dev,
> > hr_reg_enable(mpt_entry, MPT_L_INV_EN);
> >
> > hr_reg_write(mpt_entry, MPT_BIND_EN,
> > - !!(mr->access & IB_ACCESS_MW_BIND));
> > + mr->access & IB_ACCESS_MW_BIND ? 1 : 0);
>
> Err, I'm still confused where the sparse warning is coming from
Hi, Jason, i found some code in sparse/evaluate.c:
const unsigned left_not = expr->left->type == EXPR_PREOP &&
expr->left->op == '!';
const unsigned right_not = expr->right->type == EXPR_PREOP &&
expr->right->op == '!';
if ((op == '&' || op == '|') && (left_not || right_not))
warning(expr->pos, "dubious: %sx %c %sy",
I guess the "dubious" is, if somebody use "&" or "|", maybe he want
to bitwise operate a number instead of a bool.
Someone think sparse wants to remind whether he want to use a logical
"&&" instead of a bitwise "&". Maybe it is a typo.
>
> A hr_reg_write_bool() would be cleaner?
>
> Jason
