[v3,4/9] scsi: lpfc: Change to use pci_aer_clear_uncorrect_error_status()

lpfc_aer_cleanup_state() requires clearing both fatal and non-fatal
uncorrectable error status. 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(-)

[moved James, Dick, LPFC supporters to "to"]

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.

> 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)
>

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)
> >

Hi Bjorn,

> 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?

We have notified all users of the lpfc_aer_cleanup_state sysfs entry,
and Broadcom LPFC is okay to no-op.

Regards,
Justin

On Wed, Mar 15, 2023 at 2:39 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> 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)
> > >