Re: [PATCH for-rc] RDMA/srpt: Fix disabling device management

[Kamal Heib <kamalheib1@gmail.com>]

On Wed, May 13, 2020 at 02:31:18PM +0300, Leon Romanovsky wrote:
> On Wed, May 13, 2020 at 02:14:35PM +0300, Kamal Heib wrote:
> > On Wed, May 13, 2020 at 01:50:45PM +0300, Leon Romanovsky wrote:
> > > On Wed, May 13, 2020 at 01:45:36PM +0300, Kamal Heib wrote:
> > > > On Wed, May 13, 2020 at 01:21:32PM +0300, Leon Romanovsky wrote:
> > > > > On Wed, May 13, 2020 at 01:02:04PM +0300, Kamal Heib wrote:
> > > > > > On Wed, May 13, 2020 at 10:22:03AM +0300, Leon Romanovsky wrote:
> > > > > > > On Tue, May 12, 2020 at 01:29:18AM +0300, Kamal Heib wrote:
> > > > > > > > Avoid disabling device management for devices that don't support
> > > > > > > > Management datagrams (MADs) by checking if the "mad_agent" pointer is
> > > > > > > > initialized before calling ib_modify_port, also change the error message
> > > > > > > > to a warning and make it more informative.
> > > > > > > >
> > > > > > > > Fixes: 09f8a1486dca ("RDMA/srpt: Fix handling of SR-IOV and iWARP ports")
> > > > > > > > Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
> > > > > > > > ---
> > > > > > > >  drivers/infiniband/ulp/srpt/ib_srpt.c | 8 ++++++--
> > > > > > > >  1 file changed, 6 insertions(+), 2 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
> > > > > > > > index 7ed38d1cb997..7b21792ab6f7 100644
> > > > > > > > --- a/drivers/infiniband/ulp/srpt/ib_srpt.c
> > > > > > > > +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
> > > > > > > > @@ -625,14 +625,18 @@ static void srpt_unregister_mad_agent(struct srpt_device *sdev)
> > > > > > > >  		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
> > > > > > > >  	};
> > > > > > > >  	struct srpt_port *sport;
> > > > > > > > +	int ret;
> > > > > > > >  	int i;
> > > > > > > >
> > > > > > > >  	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
> > > > > > > >  		sport = &sdev->port[i - 1];
> > > > > > > >  		WARN_ON(sport->port != i);
> > > > > > > > -		if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
> > > > > > > > -			pr_err("disabling MAD processing failed.\n");
> > > > > > > >  		if (sport->mad_agent) {
> > > > > > > > +			ret = ib_modify_port(sdev->device, i, 0, &port_modify);
> > > > > > > > +			if (ret < 0)
> > > > > > > > +				pr_warn("%s-%d: disabling device management failed (%d). Note: this is expected if SR-IOV is enabled.\n",
> > > > > > > > +					dev_name(&sport->sdev->device->dev),
> > > > > > >
> > > > > > > The ib_modify_port() shouldn't be called if it expected to fail.
> > > > > > >
> > > > > > > Thanks
> > > > > >
> > > > > > OK, Do you know if there is a way to check if the created ib device is
> > > > > > for VF to avoid calling ib_modify_port()?
> > > > >
> > > > > The "is_virtfn" field inside pci_dev will give this information,
> > > > > but I don't know why it is expected to fail here.
> > > > >
> > > > > Thanks
> > > > >
> > > >
> > > > Looks like there a more trivial way, I mean checking if
> > > > IB_DEVICE_VIRTUAL_FUNCTION cap is set, probably there is a need to make
> > > > to sure that this cap is set for all providers when the IB device is
> > > > created for a VF.
> > > >
> > > > With regards to why it is expected to fail, as stated in the commit
> > > > message and the in "Fixes" commit message there is some devices (VF)
> > > > that don't support MADs.
> > >
> > > So shouldn't you test that device support MAD instead of testing VF cap?
> > >
> > > Thanks
> >
> > Correct me if I'm wrong, Do you mean check the return value from
> > rdma_cap_ib_mad()?
> 
> I think so.
> 
> Thanks
>

Well, this function will not help in the case of VFs, because the flag
that is checked in rdma_cap_ib_mad() is RDMA_CORE_CAP_IB_MAD which is
set almost for each create IB device as part of RDMA_CORE_PORT_IBA_IB or
RDMA_CORE_PORT_IBA_ROCE or RDMA_CORE_PORT_IBA_ROCE_UDP_ENCAP.

Thanks,
Kamal
> >
> > Thanks,
> > Kamal
> > >
> > > >
> > > > Thanks,
> > > > Kamal
> > > >
> > > > > >
> > > > > > Thanks,
> > > > > > Kamal
> > > > > >
> > > > > > >
> > > > > > > > +					sport->port, ret);
> > > > > > > >  			ib_unregister_mad_agent(sport->mad_agent);
> > > > > > > >  			sport->mad_agent = NULL;
> > > > > > > >  		}
> > > > > > > > --
> > > > > > > > 2.25.4
> > > > > > > >