linux-kernel - Re: [PATCH v5 05/10] PCI/AER: Apply function level reset to RCiEP on fatal error

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Message-ID: <CAAbOPF2+1xajGNuNcs3q2FapcCDRFr78EGRmopB66YuKu2G8_w@mail.gmail.com>
Date:   Tue, 22 Sep 2020 19:49:09 -0700
From:   Sean V Kelley <seanvk.dev@...gontracks.org>
To:     Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc:     Sean V Kelley <sean.v.kelley@...el.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        rafael.j.wysocki@...el.com, ashok.raj@...el.com,
        tony.luck@...el.com, sathyanarayanan.kuppuswamy@...el.com,
        qiuxu.zhuo@...el.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 05/10] PCI/AER: Apply function level reset to RCiEP on
 fatal error

On Mon, Sep 21, 2020 at 4:15 AM Jonathan Cameron
<Jonathan.Cameron@...wei.com> wrote:
>
> On Fri, 18 Sep 2020 13:45:58 -0700
> Sean V Kelley <sean.v.kelley@...el.com> wrote:
>
> > From: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
> >
> > Attempt to do function level reset for an RCiEP associated with an
> > RCEC device on fatal error.
>
> I'm not sure the description is correct. Looks like it will do
> the reset even if not associated with an RCEC.
> I'd just cut this down to:
>
> "Attempt to do a function level reset for an RCiEP on fatal error."

Agree. Will change.

>
> I'm not 100% sure doing an flr will actually help in most cass if you've
> reported a fatal error, but I suppose it does no harm!
>
> So with description changed.
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

Will do, thanks.

Sean

>
> >
> > Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
> > ---
> >  drivers/pci/pcie/err.c | 31 ++++++++++++++++++++++---------
> >  1 file changed, 22 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> > index e575fa6cee63..5380ecc41506 100644
> > --- a/drivers/pci/pcie/err.c
> > +++ b/drivers/pci/pcie/err.c
> > @@ -169,6 +169,17 @@ static void pci_bridge_walk(struct pci_dev *bridge, int (*cb)(struct pci_dev *,
> >               cb(bridge, userdata);
> >  }
> >
> > +static pci_ers_result_t flr_on_rciep(struct pci_dev *dev)
> > +{
> > +     if (!pcie_has_flr(dev))
> > +             return PCI_ERS_RESULT_NONE;
> > +
> > +     if (pcie_flr(dev))
> > +             return PCI_ERS_RESULT_DISCONNECT;
> > +
> > +     return PCI_ERS_RESULT_RECOVERED;
> > +}
> > +
> >  pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> >                       pci_channel_state_t state,
> >                       pci_ers_result_t (*reset_subordinate_devices)(struct pci_dev *pdev))
> > @@ -195,15 +206,17 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> >       if (state == pci_channel_io_frozen) {
> >               pci_bridge_walk(bridge, report_frozen_detected, &status);
> >               if (type == PCI_EXP_TYPE_RC_END) {
> > -                     pci_warn(dev, "link reset not possible for RCiEP\n");
> > -                     status = PCI_ERS_RESULT_NONE;
> > -                     goto failed;
> > -             }
> > -
> > -             status = reset_subordinate_devices(bridge);
> > -             if (status != PCI_ERS_RESULT_RECOVERED) {
> > -                     pci_warn(dev, "subordinate device reset failed\n");
> > -                     goto failed;
> > +                     status = flr_on_rciep(dev);
> > +                     if (status != PCI_ERS_RESULT_RECOVERED) {
> > +                             pci_warn(dev, "function level reset failed\n");
> > +                             goto failed;
> > +                     }
> > +             } else {
> > +                     status = reset_subordinate_devices(bridge);
> > +                     if (status != PCI_ERS_RESULT_RECOVERED) {
> > +                             pci_warn(dev, "subordinate device reset failed\n");
> > +                             goto failed;
> > +                     }
> >               }
> >       } else {
> >               pci_bridge_walk(bridge, report_normal_detected, &status);
>
>