linux-kernel - Re: [PATCH NEXT 6/6] PCI/PORTDRV: Remove ERR_FATAL handling from pcie_portdrv_slot

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Date:   Thu, 07 Jun 2018 19:18:03 +0530
From:   poza@...eaurora.org
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dongdong Liu <liudongdong3@...wei.com>,
        Keith Busch <keith.busch@...el.com>, Wei Zhang <wzhang@...com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Timur Tabi <timur@...eaurora.org>
Subject: Re: [PATCH NEXT 6/6] PCI/PORTDRV: Remove ERR_FATAL handling from
 pcie_portdrv_slot_reset()

On 2018-06-07 11:30, Oza Pawandeep wrote:
> We are handling ERR_FATAL by resetting the Link in software,skipping 
> the
> driver pci_error_handlers callbacks, removing the devices from the PCI
> subsystem, and re-enumerating, as a result of that, no more calling
> pcie_portdrv_slot_reset in ERR_FATAL case.
> 
> Signed-off-by: Oza Pawandeep <poza@...eaurora.org>
> 
> diff --git a/drivers/pci/pcie/portdrv_pci.c 
> b/drivers/pci/pcie/portdrv_pci.c
> index 973f1b8..92f5d330 100644
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -42,17 +42,6 @@ __setup("pcie_ports=", pcie_port_setup);
> 
>  /* global data */
> 
> -static int pcie_portdrv_restore_config(struct pci_dev *dev)
> -{
> -	int retval;
> -
> -	retval = pci_enable_device(dev);
> -	if (retval)
> -		return retval;
> -	pci_set_master(dev);
> -	return 0;
> -}
> -
>  #ifdef CONFIG_PM
>  static int pcie_port_runtime_suspend(struct device *dev)
>  {
> @@ -162,14 +151,6 @@ static pci_ers_result_t
> pcie_portdrv_mmio_enabled(struct pci_dev *dev)
> 
>  static pci_ers_result_t pcie_portdrv_slot_reset(struct pci_dev *dev)
>  {
> -	/* If fatal, restore cfg space for possible link reset at upstream */
> -	if (dev->error_state == pci_channel_io_frozen) {
> -		dev->state_saved = true;
> -		pci_restore_state(dev);
> -		pcie_portdrv_restore_config(dev);
> -		pci_enable_pcie_error_reporting(dev);
> -	}
> -
>  	return PCI_ERS_RESULT_RECOVERED;
>  }


Hi Bjorn,

the above patch removes ERR_FATAL handling from 
pcie_portdrv_slot_reset()
because now we are handling ERR_FATAL differently than before.

I tried to dig into pcie_portdrv_slot_reset() handling for ERR_FATAL 
case where it
restores the config space, enable device, set master and enable error 
reporting....
and as far as I understand this is being done for upstream link (bridges 
etc..)

why was it done at the first point (I checked the commit description, 
but could not really get it)
and do we need to handle the same thing in ERR_FATAL now ?

Regards,
Oza.