Date:   Wed, 15 Mar 2023 16:35:37 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Zhuo Chen <chenzhuo.1@bytedance.com>,
        James Smart <james.smart@broadcom.com>,
        Dick Kennedy <dick.kennedy@broadcom.com>
Cc:     sathyanarayanan.kuppuswamy@linux.intel.com, bhelgaas@google.com,
        ruscur@russell.cc, oohall@gmail.com, fancer.lancer@gmail.com,
        jdmason@kudzu.us, dave.jiang@intel.com, allenbh@gmail.com,
        jejb@linux.ibm.com, martin.petersen@oracle.com,
        linux-scsi@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org, ntb@lists.linux.dev,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 4/9] scsi: lpfc: Change to use
 pci_aer_clear_uncorrect_error_status()
Message-ID: <20230315213537.GA1788623@bhelgaas>
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In-Reply-To: <20221206221335.GA1363005@bhelgaas>
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On Tue, Dec 06, 2022 at 04:13:35PM -0600, Bjorn Helgaas wrote:
> On Wed, Sep 28, 2022 at 06:59:41PM +0800, Zhuo Chen wrote:
> > lpfc_aer_cleanup_state() requires clearing both fatal and non-fatal
> > uncorrectable error status.
> 
> I don't know what the point of lpfc_aer_cleanup_state() is.  AER
> errors should be handled and cleared by the PCI core, not by
> individual drivers.  Only lpfc, liquidio, and sky2 touch
> PCI_ERR_UNCOR_STATUS.
> 
> But lpfc_aer_cleanup_state() is visible in the
> "lpfc_aer_state_cleanup" sysfs file, so removing it would break any
> userspace that uses it.
> 
> If we can rely on the PCI core to clean up AER errors itself
> (admittedly, that might be a big "if"), maybe lpfc_aer_cleanup_state()
> could just become a no-op?
> 
> Any comment from the LPFC folks?
> 
> Ideally, I would rather not export pci_aer_clear_nonfatal_status() or
> pci_aer_clear_uncorrect_error_status() outside the PCI core at all.

Resurrecting this old thread.  Zhuo, can you figure out where the PCI
core clears these errors, include that in the commit log, and propose
a patch that makes lpfc_aer_cleanup_state() a no-op, by removing the
pci_aer_clear_nonfatal_status() call completely?

Such a patch could be sent to the SCSI maintainers since it doesn't
involve the PCI core.

If it turns out that the PCI core *doesn't* clear these errors, we
should figure out *why* it doesn't and try to change the PCI core so
it does.

> > But using pci_aer_clear_nonfatal_status()
> > will only clear non-fatal error status. To clear both fatal and
> > non-fatal error status, use pci_aer_clear_uncorrect_error_status().
> > 
> > Signed-off-by: Zhuo Chen <chenzhuo.1@bytedance.com>
> > ---
> >  drivers/scsi/lpfc/lpfc_attr.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
> > index 09cf2cd0ae60..d835cc0ba153 100644
> > --- a/drivers/scsi/lpfc/lpfc_attr.c
> > +++ b/drivers/scsi/lpfc/lpfc_attr.c
> > @@ -4689,7 +4689,7 @@ static DEVICE_ATTR_RW(lpfc_aer_support);
> >   * Description:
> >   * If the @buf contains 1 and the device currently has the AER support
> >   * enabled, then invokes the kernel AER helper routine
> > - * pci_aer_clear_nonfatal_status() to clean up the uncorrectable
> > + * pci_aer_clear_uncorrect_error_status() to clean up the uncorrectable
> >   * error status register.
> >   *
> >   * Notes:
> > @@ -4715,7 +4715,7 @@ lpfc_aer_cleanup_state(struct device *dev, struct device_attribute *attr,
> >  		return -EINVAL;
> >  
> >  	if (phba->hba_flag & HBA_AER_ENABLED)
> > -		rc = pci_aer_clear_nonfatal_status(phba->pcidev);
> > +		rc = pci_aer_clear_uncorrect_error_status(phba->pcidev);
> >  
> >  	if (rc == 0)
> >  		return strlen(buf);
> > -- 
> > 2.30.1 (Apple Git-130)
> >