Re: [PATCH v15 1/5] PCI/ERR: Update error status after reset_link()

Bjorn Helgaas
2020-02-26T13:41:55Z

On Thu, Feb 13, 2020 at 10:20:13AM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>
> Commit bdb5ac85777d ("PCI/ERR: Handle fatal error recovery") uses
> reset_link() to recover from fatal errors. But during fatal error
> recovery, if the initial value of error status is
> PCI_ERS_RESULT_DISCONNECT or PCI_ERS_RESULT_NO_AER_DRIVER then
> even after successful recovery (using reset_link()) pcie_do_recovery()
> will report the recovery result as failure. So update the status of
> error after reset_link().
>
> Fixes: bdb5ac85777d ("PCI/ERR: Handle fatal error recovery")
> Cc: Ashok Raj <ashok.raj@intel.com>
> Cc: Keith Busch <keith.busch@intel.com>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Acked-by: Keith Busch <keith.busch@intel.com>

I raised the possibility of a stable tag for this. If you'd like
that, please add the tag and some justification per
Documentation/process/stable-kernel-rules.rst.

A kernel.org bugzilla pointer to show the user-visible effect of this,
e.g., "lspci -vv" and a dmesg log showing an error that should be
recoverable but isn't, would be a good start. That would actually be
useful even if you don't want a stable tag.

> ---
> drivers/pci/pcie/err.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index 01dfc8bb7ca0..eefefe03857a 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -208,9 +208,11 @@ void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
> else
> pci_walk_bus(bus, report_normal_detected, &status);
>
> - if (state == pci_channel_io_frozen &&
> - reset_link(dev, service) != PCI_ERS_RESULT_RECOVERED)
> - goto failed;
> + if (state == pci_channel_io_frozen) {
> + status = reset_link(dev, service);
> + if (status != PCI_ERS_RESULT_RECOVERED)
> + goto failed;
> + }
>
> if (status == PCI_ERS_RESULT_CAN_RECOVER) {
> status = PCI_ERS_RESULT_RECOVERED;
> --
> 2.21.0
>