Subject: Re: [PATCH 1/6] powerpc/eeh: Add sysfs files in late probe

From: Sam Bobroff <[email-masked]>
Date: Thu, 6 Feb 2020 15:13:12 +1100

On Mon, Feb 03, 2020 at 07:35:16PM +1100, Oliver O'Halloran wrote:
> Move creating the EEH specific sysfs files into eeh_add_device_late()
> rather than being open-coded all over the place. Calling the function is
> generally done immediately after calling eeh_add_device_late() anyway. The
> two cases where it's not done there (OF based PCI probing and the pseries
> VFs) don't seem to have any issues with the re-ordering.

I haven't tested it explicitly, but I suspect the re-ordering will
actually improve things: in some error cases it will no longer add sysfs
files for devices that have failed to init, because bailing out in
eeh_add_device_late() (or eeh_probve_device()) will now prevent
eeh_sysfs_add_device() from being called.

Nice cleanup.

Reviewed-by: Sam Bobroff <[email-masked]>

> Signed-off-by: Oliver O'Halloran <[email-masked]>
> ---
>  arch/powerpc/include/asm/eeh.h               |  3 ---
>  arch/powerpc/kernel/eeh.c                    | 24 +-----------------------
>  arch/powerpc/kernel/of_platform.c            |  3 ---
>  arch/powerpc/kernel/pci-common.c             |  3 ---
>  arch/powerpc/platforms/powernv/eeh-powernv.c |  1 -
>  arch/powerpc/platforms/pseries/eeh_pseries.c |  3 +--
>  6 files changed, 2 insertions(+), 35 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> index 6f9b2a1..5a34907 100644
> --- a/arch/powerpc/include/asm/eeh.h
> +++ b/arch/powerpc/include/asm/eeh.h
> @@ -305,7 +305,6 @@ void eeh_add_device_early(struct pci_dn *);
>  void eeh_add_device_tree_early(struct pci_dn *);
>  void eeh_add_device_late(struct pci_dev *);
>  void eeh_add_device_tree_late(struct pci_bus *);
> -void eeh_add_sysfs_files(struct pci_bus *);
>  void eeh_remove_device(struct pci_dev *);
>  int eeh_unfreeze_pe(struct eeh_pe *pe);
>  int eeh_pe_reset_and_recover(struct eeh_pe *pe);
> @@ -368,8 +367,6 @@ static inline void eeh_add_device_late(struct pci_dev *dev) { }
>  
>  static inline void eeh_add_device_tree_late(struct pci_bus *bus) { }
>  
> -static inline void eeh_add_sysfs_files(struct pci_bus *bus) { }
> -
>  static inline void eeh_remove_device(struct pci_dev *dev) { }
>  
>  #define EEH_POSSIBLE_ERROR(val, type) (0)
> diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
> index 17cb3e9..0878912 100644
> --- a/arch/powerpc/kernel/eeh.c
> +++ b/arch/powerpc/kernel/eeh.c
> @@ -1210,6 +1210,7 @@ void eeh_add_device_late(struct pci_dev *dev)
>  	dev->dev.archdata.edev = edev;
>  
>  	eeh_addr_cache_insert_dev(dev);
> +	eeh_sysfs_add_device(dev);
>  }
>  
>  /**
> @@ -1238,29 +1239,6 @@ void eeh_add_device_tree_late(struct pci_bus *bus)
>  EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
>  
>  /**
> - * eeh_add_sysfs_files - Add EEH sysfs files for the indicated PCI bus
> - * @bus: PCI bus
> - *
> - * This routine must be used to add EEH sysfs files for PCI
> - * devices which are attached to the indicated PCI bus. The PCI bus
> - * is added after system boot through hotplug or dlpar.
> - */
> -void eeh_add_sysfs_files(struct pci_bus *bus)
> -{
> -	struct pci_dev *dev;
> -
> -	list_for_each_entry(dev, &bus->devices, bus_list) {
> -		eeh_sysfs_add_device(dev);
> -		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> -			struct pci_bus *subbus = dev->subordinate;
> -			if (subbus)
> -				eeh_add_sysfs_files(subbus);
> -		}
> -	}
> -}
> -EXPORT_SYMBOL_GPL(eeh_add_sysfs_files);
> -
> -/**
>   * eeh_remove_device - Undo EEH setup for the indicated pci device
>   * @dev: pci device to be removed
>   *
> diff --git a/arch/powerpc/kernel/of_platform.c b/arch/powerpc/kernel/of_platform.c
> index 427fc22..cb68800 100644
> --- a/arch/powerpc/kernel/of_platform.c
> +++ b/arch/powerpc/kernel/of_platform.c
> @@ -86,9 +86,6 @@ static int of_pci_phb_probe(struct platform_device *dev)
>  	/* Add probed PCI devices to the device model */
>  	pci_bus_add_devices(phb->bus);
>  
> -	/* sysfs files should only be added after devices are added */
> -	eeh_add_sysfs_files(phb->bus);
> -

So for this case, the sysfs files are added by pci_bus_add_devices(),
via...
	pci_bus_add_devices() (loops over devices) ->
	pci_bus_add_device() ->
	pcibios_bus_add_device() ->
	ppc_md.pcibios_bus_add_device() ->
	{pseries,pnv}_pcibios_bus_add_device() ->
	eeh_add_device_late() ->
	eeh_sysfs_add_device().

>  	return 0;
>  }
>  
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index c6c0341..3d2b1cf 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -1404,9 +1404,6 @@ void pcibios_finish_adding_to_bus(struct pci_bus *bus)
>  
>  	/* Add new devices to global lists.  Register in proc, sysfs. */
>  	pci_bus_add_devices(bus);
> -
> -	/* sysfs files should only be added after devices are added */
> -	eeh_add_sysfs_files(bus);

As above.

>  }
>  EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);
>  
> diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
> index 6f300ab..ef727ec 100644
> --- a/arch/powerpc/platforms/powernv/eeh-powernv.c
> +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
> @@ -48,7 +48,6 @@ void pnv_pcibios_bus_add_device(struct pci_dev *pdev)
>  	dev_dbg(&pdev->dev, "EEH: Setting up device\n");
>  	eeh_add_device_early(pdn);
>  	eeh_add_device_late(pdev);
> -	eeh_sysfs_add_device(pdev);

So for this case, the sysfs files are added by eeh_add_device_late(),
via...
	eeh_add_device_late() ->
	eeh_sysfs_add_device().

>  }
>  
>  static int pnv_eeh_init(void)
> diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c
> index 893ba3f..95bbf91 100644
> --- a/arch/powerpc/platforms/pseries/eeh_pseries.c
> +++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
> @@ -68,7 +68,6 @@ void pseries_pcibios_bus_add_device(struct pci_dev *pdev)
>  	}
>  #endif
>  	eeh_add_device_early(pdn);
> -	eeh_add_device_late(pdev);
>  #ifdef CONFIG_PCI_IOV
>  	if (pdev->is_virtfn) {
>  		struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
> @@ -78,7 +77,7 @@ void pseries_pcibios_bus_add_device(struct pci_dev *pdev)
>  		eeh_add_to_parent_pe(edev);   /* Add as VF PE type */
>  	}
>  #endif
> -	eeh_sysfs_add_device(pdev);
> +	eeh_add_device_late(pdev);

This is just a re-ordering.

>  }
>  /*
> -- 
> 2.9.5