On Fri, Oct 09, 2020 at 03:52:51AM +0100, Hedi Berriche wrote:
> Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
> changed pcie_do_recovery() so that status is updated with the return
> value from reset_link(); this was to fix the problem where we would
> wrongly report recovery failure, despite a successful reset_link(),
> whenever the initial error status is PCI_ERS_RESULT_DISCONNECT or
> PCI_ERS_RESULT_NO_AER_DRIVER.
>
> Unfortunately this breaks the flow of pcie_do_recovery() as it prevents
What is the reference to "this breaks" above?
> the actions needed when the initial error is PCI_ERS_RESULT_CAN_RECOVER
> or PCI_ERS_RESULT_NEED_RESET from taking place which causes error
> recovery to fail.
>
> Don't clobber status after reset_link() to restore the intended flow in
> pcie_do_recovery().
>
> Fix the original problem by saving the return value from reset_link()
> and use it later on to decide whether error recovery should be deemed
> successful in the scenarios where the initial error status is
> PCI_ERS_RESULT_{DISCONNECT,NO_AER_DRIVER}.
I would rather rephrase the above to make it clear what is being proposed.
Since the description seems to talk about the old problem and new solution
all mixed up.
>
> Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
> Signed-off-by: Hedi Berriche <hedi.berriche@xxxxxxx>
> Cc: Russ Anderson <rja@xxxxxxx>
> Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Keith Busch <keith.busch@xxxxxxxxx>
> Cc: Joerg Roedel <jroedel@xxxxxxxx>
>
> Cc: stable@xxxxxxxxxx # v5.7+
> ---
> drivers/pci/pcie/err.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index c543f419d8f9..dbd0b56bd6c1 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -150,7 +150,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_channel_state_t state,
> pci_ers_result_t (*reset_link)(struct pci_dev *pdev))
> {
> - pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> + pci_ers_result_t post_reset_status, status = PCI_ERS_RESULT_CAN_RECOVER;
why call it post_reset_status?
> struct pci_bus *bus;
>
> /*
> @@ -165,8 +165,8 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_dbg(dev, "broadcast error_detected message\n");
> if (state == pci_channel_io_frozen) {
> pci_walk_bus(bus, report_frozen_detected, &status);
> - status = reset_link(dev);
> - if (status != PCI_ERS_RESULT_RECOVERED) {
> + post_reset_status = reset_link(dev);
> + if (post_reset_status != PCI_ERS_RESULT_RECOVERED) {
> pci_warn(dev, "link reset failed\n");
> goto failed;
> }
> @@ -174,6 +174,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_walk_bus(bus, report_normal_detected, &status);
> }
>
> + if ((status == PCI_ERS_RESULT_DISCONNECT ||
> + status == PCI_ERS_RESULT_NO_AER_DRIVER) &&
> + post_reset_status == PCI_ERS_RESULT_RECOVERED) {
> + /* error recovery succeeded thanks to reset_link() */
> + status = PCI_ERS_RESULT_RECOVERED;
> + }
> +
> if (status == PCI_ERS_RESULT_CAN_RECOVER) {
> status = PCI_ERS_RESULT_RECOVERED;
> pci_dbg(dev, "broadcast mmio_enabled message\n");
> --
> 2.28.0
>
