On Mon, 2020-03-30 at 15:56 +1100, Sam Bobroff wrote:
> When EEH device state was released asynchronously by the device
> release handler, it was possible for an outstanding reference to
> prevent it's release and it was necessary to work around that if a
> device was re-discovered at the same PCI location.
I think this is a bit misleading. The main situation where you'll hit
this hack is when recovering a device with a driver that doesn't
implement the error handling callbacks. In that case the device is
removed, reset, then re-probed by the PCI core, but we assume it's the
same physical device so the eeh_device state remains active.
If you actually changed the underlying device I suspect something bad
would happen.
> Now that the state is released synchronously that is no longer
> possible and the workaround is no longer necessary.
You could probably fold this into the previous patch, but eh. You could
probably fold this into the previous patch, but eh.
> Signed-off-by: Sam Bobroff <sbobr...@linux.ibm.com>
> ---
> arch/powerpc/kernel/eeh.c | 23 +----------------------
> 1 file changed, 1 insertion(+), 22 deletions(-)
>
> diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
> index c36c5a7db5ca..12c248a16527 100644
> --- a/arch/powerpc/kernel/eeh.c
> +++ b/arch/powerpc/kernel/eeh.c
> @@ -1206,28 +1206,7 @@ void eeh_add_device_late(struct pci_dev *dev)
> eeh_edev_dbg(edev, "Device already referenced!\n");
> return;
> }
> -
> - /*
> - * The EEH cache might not be removed correctly because of
> - * unbalanced kref to the device during unplug time, which
> - * relies on pcibios_release_device(). So we have to remove
> - * that here explicitly.
> - */
> - if (edev->pdev) {
> - eeh_rmv_from_parent_pe(edev);
> - eeh_addr_cache_rmv_dev(edev->pdev);
> - eeh_sysfs_remove_device(edev->pdev);
> -
> - /*
> - * We definitely should have the PCI device removed
> - * though it wasn't correctly. So we needn't call
> - * into error handler afterwards.
> - */
> - edev->mode |= EEH_DEV_NO_HANDLER;
> -
> - edev->pdev = NULL;
> - dev->dev.archdata.edev = NULL;
> - }
> + WARN_ON_ONCE(edev->pdev);
>
> if (eeh_has_flag(EEH_PROBE_MODE_DEV))
> eeh_ops->probe(pdn, NULL);
