Re: [PATCH rdma-next 4/6] RDMA/cm: Delete useless QPN masking

[Leon Romanovsky <leon@kernel.org>]

On Mon, Oct 28, 2019 at 09:52:33AM -0300, Jason Gunthorpe wrote:
> On Sun, Oct 20, 2019 at 10:15:57AM +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@mellanox.com>
> >
> > QPN is supplied by kernel users who controls and creates valid QPs,
> > such flow ensures that QPN is limited to 24bits and no need to mask
> > already valid QPN.
> >
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> > ---
> >  drivers/infiniband/core/cm.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> > index 7ffa16ea5fe3..2eb8e1fab962 100644
> > --- a/drivers/infiniband/core/cm.c
> > +++ b/drivers/infiniband/core/cm.c
> > @@ -2101,7 +2101,7 @@ int ib_send_cm_rep(struct ib_cm_id *cm_id,
> >  	cm_id_priv->initiator_depth = param->initiator_depth;
> >  	cm_id_priv->responder_resources = param->responder_resources;
> >  	cm_id_priv->rq_psn = cm_rep_get_starting_psn(rep_msg);
> > -	cm_id_priv->local_qpn = cpu_to_be32(param->qp_num & 0xFFFFFF);
> > +	cm_id_priv->local_qpn = cpu_to_be32(param->qp_num);
>
> It does seem like this value comes from userspace:
>
> ucma_connect()
>   ucma_copy_conn_param()
>     	dst->qp_num = src->qp_num
>   rdma_connect(.., &dst)
> 	if (!id->qp) {
> 		id_priv->qp_num = conn_param->qp_num;
>
> vs
>
> cma_accept_ib()
> 	rep.qp_num = id_priv->qp_num;
>
> Maybe this needs to add some masking to ucma_copy_conn_param()?

Thanks for the callstack, Or pointed it to me too, but I missed this flow.
Let's create a pre-patch with QPN masking.

Thanks

>
> Jason