Re: [PATCH for-next v3 1/4] RDMA/core: Fix return code when modify_port isn't supported

[Kamal Heib <kamalheib1@gmail.com>]

On Tue, Oct 22, 2019 at 04:20:02PM -0300, Jason Gunthorpe wrote:
> On Fri, Oct 18, 2019 at 12:41:12PM +0300, Kamal Heib wrote:
> > Improving return code from ib_modify_port() by doing the following:
> > 1- Use "-EOPNOTSUPP" instead "-ENOSYS" which is the proper return code.
> > 2- Avoid confusion by return "-EOPNOTSUPP" when modify_port() isn't
> >    supplied by the provider and the protocol is IB, otherwise return
> >    success to avoid failure of the ib_modify_port() in CM layer.
> > 
> > Fixes: 61e0962d5221 ("IB: Avoid ib_modify_port() failure for RoCE devices")
> > Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
> >  drivers/infiniband/core/device.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> > index a667636f74bf..626ac18dd3a7 100644
> > +++ b/drivers/infiniband/core/device.c
> > @@ -2397,7 +2397,7 @@ int ib_modify_port(struct ib_device *device,
> >  					     port_modify_mask,
> >  					     port_modify);
> >  	else
> > -		rc = rdma_protocol_roce(device, port_num) ? 0 : -ENOSYS;
> > +		rc = rdma_protocol_ib(device, port_num) ? -EOPNOTSUPP : 0;
> >  	return rc;
> 
> Oh gross, this is such an ugly hack
> 
> roce mode should allow a fake IB_PORT_CM_SUP to be manipulated and
> nothing else.
> 
> All other cases should return EOPNOTSUPP as something has gone really
> wrong
> 
> Jason

Do you mean something like the following:

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index a667636f74bf..1db97f6f5dec 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -2396,8 +2396,12 @@ int ib_modify_port(struct ib_device *device,
                rc = device->ops.modify_port(device, port_num,
                                             port_modify_mask,
                                             port_modify);
+       else if (rdma_protocol_roce(device, port_num) &&
+                ((port_modify->set_port_cap_mask & IB_PORT_CM_SUP) ||
+                (port_modify->clr_port_cap_mask & IB_PORT_CM_SUP)))
+               rc = 0;
        else
-               rc = rdma_protocol_roce(device, port_num) ? 0 : -ENOSYS;
+               rc = -EOPNOTSUPP;
        return rc;
 }
 EXPORT_SYMBOL(ib_modify_port);