Subject: Re: [PATCH 05/31] powerpc/eeh: Trace PCI bus from PE

From: Mike Qiu <[email-masked]>
Date: Wed, 19 Jun 2013 15:21:07 +0800

于 2013/6/18 16:33, Gavin Shan 写道:
> There're several types of PEs can be supported for now: PHB, Bus
> and Device dependent PE. For PCI bus dependent PE, tracing the
> corresponding PCI bus from PE (struct eeh_pe) would make the code
> more efficient. The patch also enables the retrieval of PCI bus based
> on the PCI bus dependent PE.
>
> Signed-off-by: Gavin Shan <[email-masked]>
> ---
>   arch/powerpc/include/asm/eeh.h |    1 +
>   arch/powerpc/kernel/eeh_pe.c   |   22 ++++++++++++++++++++++
>   2 files changed, 23 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> index acdfcaa..f3b49d6 100644
> --- a/arch/powerpc/include/asm/eeh.h
> +++ b/arch/powerpc/include/asm/eeh.h
> @@ -59,6 +59,7 @@ struct eeh_pe {
>   	int config_addr;		/* Traditional PCI address	*/
>   	int addr;			/* PE configuration address	*/
>   	struct pci_controller *phb;	/* Associated PHB		*/
> +	struct pci_bus *bus;		/* Top PCI bus for bus PE	*/
>   	int check_count;		/* Times of ignored error	*/
>   	int freeze_count;		/* Times of froze up		*/
>   	int false_positives;		/* Times of reported #ff's	*/
> diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
> index 3d2dcf5..5bd1637 100644
> --- a/arch/powerpc/kernel/eeh_pe.c
> +++ b/arch/powerpc/kernel/eeh_pe.c
> @@ -304,6 +304,7 @@ static struct eeh_pe *eeh_pe_get_parent(struct eeh_dev *edev)
>   int eeh_add_to_parent_pe(struct eeh_dev *edev)
>   {
>   	struct eeh_pe *pe, *parent;
> +	struct eeh_dev *first_edev;
>
>   	eeh_lock();
>
> @@ -326,6 +327,21 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
>   		pe->type = EEH_PE_BUS;
>   		edev->pe = pe;
>
> +		/*
> +		 * For PCI bus sensitive PE, we can reset the parent
> +		 * bridge in order for hot-reset. However, the PCI
> +		 * devices including the associated EEH devices might
> +		 * be removed when EEH core is doing recovery. So that
> +		 * won't safe to retrieve the bridge through downstream
> +		 * EEH device. We have to trace the parent PCI bus, then
> +		 * the parent bridge explicitly.
> +		 */
> +		if (eeh_probe_mode_dev() && !pe->bus) {
> +			first_edev = list_first_entry(&pe->edevs,
> +						      struct eeh_dev, list);
> +			pe->bus = eeh_dev_to_pci_dev(first_edev)->bus;
> +		}
Hi Gavin

I have qestion, can we keep pe->bus for a device pe ? the value is the 
bus which edev belongs to.

so that we can make the code more efficient for device pe.

I have no idea of whether this will cause side effect

Thanks
Mike
> +
>   		/* Put the edev to PE */
>   		list_add_tail(&edev->list, &pe->edevs);
>   		eeh_unlock();
> @@ -641,12 +657,18 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
>   		bus = pe->phb->bus;
>   	} else if (pe->type & EEH_PE_BUS ||
>   		   pe->type & EEH_PE_DEVICE) {
> +		if (pe->bus) {
> +			bus = pe->bus;
> +			goto out;
> +		}
> +
>   		edev = list_first_entry(&pe->edevs, struct eeh_dev, list);
>   		pdev = eeh_dev_to_pci_dev(edev);
>   		if (pdev)
>   			bus = pdev->bus;
>   	}
>
> +out:
>   	eeh_unlock();
>
>   	return bus;