Re: [PATCH v2 2/3] ACPI/APEI: Force fatal AER severity when bus hasbeen reset

[Chen Gong]

On Tue, Jun 04, 2013 at 11:54:34AM -0600, Bjorn Helgaas wrote:
> Date:	Tue, 4 Jun 2013 11:54:34 -0600
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> To: Betty Dall <betty.dall@xxxxxx>, rjw@xxxxxxx, ying.huang@xxxxxxxxx,
>  linux-acpi@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx,
>  linux-pci@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 2/3] ACPI/APEI: Force fatal AER severity when bus
>  has been reset
> User-Agent: Mutt/1.5.21 (2010-09-15)
> 
> On Tue, Jun 04, 2013 at 03:53:36AM -0400, Chen Gong wrote:
> > On Thu, May 30, 2013 at 08:39:28AM -0600, Betty Dall wrote:
> > > Date:	Thu, 30 May 2013 08:39:28 -0600
> > > From: Betty Dall <betty.dall@xxxxxx>
> > > To: rjw@xxxxxxx, bhelgaas@xxxxxxxxxx
> > > Cc: ying.huang@xxxxxxxxx, linux-acpi@xxxxxxxxxxxxxxx,
> > >  linux-kernel@xxxxxxxxxxxxxxx, linux-pci@xxxxxxxxxxxxxxx, Betty Dall
> > >  <betty.dall@xxxxxx>
> > > Subject: [PATCH v2 2/3] ACPI/APEI: Force fatal AER severity when bus has
> > >  been reset
> > > X-Mailer: git-send-email 1.7.7.6
> > > 
> > > The CPER error record has a reset bit that indicates that the platform
> > > has reset the bus. The reset bit can be set for any severity error
> > > including recoverable.  From the AER code path's perspective,
> > > any error is fatal if the bus has been reset. This patch upgrades the
> > > severity of the AER recovery to AER_FATAL whenever the CPER error record
> > > indicates that the bus has been reset.
> > > 
> > > Changes since v1:
> > > Fixed a typo in comment.
> > > 
> > > Signed-off-by: Betty Dall <betty.dall@xxxxxx>
> > > ---
> > > 
> > >  drivers/acpi/apei/ghes.c |   21 ++++++++++++++++++++-
> > >  1 files changed, 20 insertions(+), 1 deletions(-)
> > > 
> > > 
> > > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> > > index d668a8a..1c67d5a 100644
> > > --- a/drivers/acpi/apei/ghes.c
> > > +++ b/drivers/acpi/apei/ghes.c
> > > @@ -451,7 +451,26 @@ static void ghes_do_proc(struct ghes *ghes,
> > >  				int aer_severity;
> > >  				devfn = PCI_DEVFN(pcie_err->device_id.device,
> > >  						  pcie_err->device_id.function);
> > > -				aer_severity = cper_severity_to_aer(sev);
> > > +				/*
> > > +				 * Some Firmware First implementations
> > > +				 * put the device in SBR to contain
> > > +				 * the error. This is indicated by the
> > > +				 * CPER Section Descriptor Flags reset
> > > +				 * bit which means the component must
> > > +				 * be re-initialized or re-enabled
> > > +				 * prior to use. Promoting the AER
> > > +				 * serverity to FATAL will cause the
> > > +				 * AER code to link_reset and allow
> > > +				 * drivers to reprogram their cards.
> > > +				 */
> > > +				if (gdata->flags & CPER_SEC_RESET)
> > > +					aer_severity = cper_severity_to_aer(
> > > +							CPER_SEV_FATAL);
> > > +				else
> > > +					aer_severity =
> > > +						cper_severity_to_aer(sev);
> > > +
> > > +
> > 
> > How about this?
> >                                 if (gdata->flags & CPER_SEC_RESET)
> >                                         sev = CPER_SEV_FATAL;
> >                                 cper_severity_to_aer(sev);
> 
> No.  If the object is to make the severity AER_FATAL, you should just
> do that.  You shouldn't fiddle around with the CPER severity, because
> then you depend on the mapping performed by cper_severity_to_aer().
> 
> > 
> > >  				aer_recover_queue(pcie_err->device_id.segment,
> > >  						  pcie_err->device_id.bus,
> > >  						  devfn, aer_severity);
> 
> In other words, something like the patch below.  I don't really care
> if you use the original "if" above that only sets aer_severity once,
> or if you overwrite it as below.  I overwrote it because it doesn't
> wrap as many lines.  ghes_do_proc() really should just call helpers
> so the interesting code doesn't have to be indented three and four
> tab stops.
> 
> 
> ACPI/APEI: Force fatal AER severity when component has been reset
>     
> The CPER error record has a reset bit that indicates that the platform has
> reset the component.  The reset bit can be set for any severity error
> including recoverable.  From the AER code path's perspective, any error is
> fatal if the component has been reset. This patch upgrades the severity of
> the AER recovery to AER_FATAL in this case.
>     
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index d668a8a..ab31551 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -449,9 +449,19 @@ static void ghes_do_proc(struct ghes *ghes,
>  			    pcie_err->validation_bits & CPER_PCIE_VALID_AER_INFO) {
>  				unsigned int devfn;
>  				int aer_severity;
> +
>  				devfn = PCI_DEVFN(pcie_err->device_id.device,
>  						  pcie_err->device_id.function);
>  				aer_severity = cper_severity_to_aer(sev);
> +
> +				/*
> +				 * If firmware reset the component to contain
> +				 * the error, we must reinitialize it before
> +				 * use, so treat it as a fatal AER error.
> +				 */
> +				if (gdata->flags & CPER_SEC_RESET)
> +					aer_severity = AER_FATAL;
> +
>  				aer_recover_queue(pcie_err->device_id.segment,
>  						  pcie_err->device_id.bus,
>  						  devfn, aer_severity);
>

The patch looks good to me.

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