Re: [PATCH rdma-next 2/3] IB/cm: remove cm_id_priv->id.service_mask and service_mask parameter of cm_init_listen()

[Leon Romanovsky <leonro@nvidia.com>]

On Sun, Aug 21, 2022 at 08:50:08PM +0800, Mark Zhang wrote:
> On 8/21/2022 7:34 PM, Leon Romanovsky wrote:
> > On Fri, Aug 19, 2022 at 12:08:58PM +0300, Mark Zhang wrote:
> > > The service_mask is always ~cpu_to_be64(0), so the result is always
> > > a NOP when it is &'d with a service_id. Remove it for simplicity.
> > > 
> > > Signed-off-by: Mark Zhang <markzhang@nvidia.com>
> > > ---
> > >   drivers/infiniband/core/cm.c | 28 ++++++++--------------------
> > >   include/rdma/ib_cm.h         |  1 -
> > >   2 files changed, 8 insertions(+), 21 deletions(-)

<...>

> > > -	if (service_id == IB_CM_ASSIGN_SERVICE_ID) {
> > > +	if (service_id == IB_CM_ASSIGN_SERVICE_ID)
> > >   		cm_id_priv->id.service_id = cpu_to_be64(cm.listen_service_id++);
> > > -		cm_id_priv->id.service_mask = ~cpu_to_be64(0);
> > > -	} else {
> > > +	else
> > >   		cm_id_priv->id.service_id = service_id;
> > > -		cm_id_priv->id.service_mask = service_mask;
> > > -	}
> > 
> > If service_id != IB_CM_ASSIGN_SERVICE_ID, we had zero as service_mask
> > and not FFF... like you wrote. It puts in question all
> > cm_id_priv->id.service_mask & service_id => service_id conversions in
> > this patch.
> 
> The id.service_mask field is removed in this patch, check the change in
> include/rdma/ib_cm.h

Right, you removed service_mask and described it "is always ~cpu_to_be64(0)".
As far as I can tell, this is not true and in this "if (service_id == IB_CM_ASSIGN_SERVICE_ID)"
sometimes we set cm_id_priv->id.service_mask to be 0 and sometimes 0xFF....

Why is it correct to remove cm_id_priv->id.service_mask in this hunk?

Thanks