[PATCH] cxl: Route eeh events to all drivers in cxl_pci_error_detected()

[Andrew Donnellan]

On 05/04/17 16:16, Vaibhav Jain wrote:
> Fix a boundary condition where in some cases an eeh event that results
> in card reset isn't passed on to a driver attached to the virtual PCI
> device associated with a slice. This will happen in case when a slice
> attached device driver returns a value other than
> PCI_ERS_RESULT_NEED_RESET from the eeh error_detected() callback. This
> would result in an early return from cxl_pci_error_detected() and
> other drivers attached to other AFUs on the card wont be notified.
>
> The patch fixes this by making sure that all slice attached
> device-drivers are notified and the return values from
> error_detected() callback are aggregated in a scheme where request for
> 'disconnect' trumps all and 'none' trumps 'need_reset'.
>
> Based-on: https://patchwork.ozlabs.org/patch/747102/
> Fixes: 9e8df8a21963("cxl: EEH support")
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

Should this go to stable?

> ---
>  drivers/misc/cxl/pci.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index 1e98245..701f6a3 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -1782,7 +1782,7 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
>  {
>  	struct cxl *adapter = pci_get_drvdata(pdev);
>  	struct cxl_afu *afu;
> -	pci_ers_result_t result = PCI_ERS_RESULT_NEED_RESET;
> +	pci_ers_result_t result = PCI_ERS_RESULT_NEED_RESET, afu_result;
>  	int i;
>
>  	/* At this point, we could still have an interrupt pending.
> @@ -1886,15 +1886,18 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
>  	for (i = 0; i < adapter->slices; i++) {
>  		afu = adapter->afu[i];
>
> -		result = cxl_vphb_error_detected(afu, state);
> -
> -		/* Only continue if everyone agrees on NEED_RESET */
> -		if (result != PCI_ERS_RESULT_NEED_RESET)
> -			return result;
> +		afu_result = cxl_vphb_error_detected(afu, state);
>
>  		cxl_context_detach_all(afu);
>  		cxl_ops->afu_deactivate_mode(afu, afu->current_mode);
>  		pci_deconfigure_afu(afu);
> +
> +		/* Disconnect trumps all, NONE trumps NEED_RESET */
> +		if (afu_result == PCI_ERS_RESULT_DISCONNECT)
> +			result = PCI_ERS_RESULT_DISCONNECT;
> +		else if ((afu_result == PCI_ERS_RESULT_NONE) &&
> +			 (result == PCI_ERS_RESULT_NEED_RESET))
> +			result = PCI_ERS_RESULT_NONE;
>  	}
>
>  	/* should take the context lock here */
>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited