linux-kernel - Re: [PATCH v11 4/5] PCI/portdrv: Remove redundant pci_aer

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Date:   Mon, 2 Nov 2020 17:59:57 +0800
From:   Ethan Zhao <xerces.zhao@...il.com>
To:     "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>,
        linux-pci <linux-pci@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ashok Raj <ashok.raj@...el.com>, knsathya@...nel.org
Subject: Re: [PATCH v11 4/5] PCI/portdrv: Remove redundant pci_aer_available()
 check in DPC enable logic

The current logic is
if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    pci_aer_available() &&
    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
services |= PCIE_PORT_SERVICE_DPC;


if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    pci_aer_available() &&
    (pcie_ports_dpc_native))
 services |= PCIE_PORT_SERVICE_DPC;

or

if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    pci_aer_available() &&(services & PCIE_PORT_SERVICE_AER)）
  services |= PCIE_PORT_SERVICE_DPC;

do you mean one of the possible is
if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    (pcie_ports_dpc_native))
 services |= PCIE_PORT_SERVICE_DPC;

after your patch ? nothing about AER ?

Thanks,
Ethan

On Thu, Oct 29, 2020 at 1:14 AM Kuppuswamy, Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com> wrote:
>
>
>
> On 10/27/20 11:00 PM, Ethan Zhao wrote:
> > On Tue, Oct 27, 2020 at 10:00 PM Kuppuswamy Sathyanarayanan
> > <sathyanarayanan.kuppuswamy@...ux.intel.com> wrote:
> >>
> >> In DPC service enable logic, check for
> >> services & PCIE_PORT_SERVICE_AER implies pci_aer_available()
> > How about PCIE_PORT_SERVICE_AER is not configured, but
> > pcie_aer_disable == 0 ？
> Its not possible in current code flow. DPC service is configured
> following AER service configuration.
> >> is true. So there is no need to explicitly check it again.
> >>
> >> Also, passing pcie_ports=dpc-native in kernel command line
> >> implies DPC needs to be enabled in native mode irrespective
> >> of AER ownership status. So checking for pci_aer_available()
> >> without checking for pcie_ports status is incorrect.
> >>
> >> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> >> ---
> >>   drivers/pci/pcie/portdrv_core.c | 1 -
> >>   1 file changed, 1 deletion(-)
> >>
> >> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> >> index 2c0278f0fdcc..e257a2ca3595 100644
> >> --- a/drivers/pci/pcie/portdrv_core.c
> >> +++ b/drivers/pci/pcie/portdrv_core.c
> >> @@ -252,7 +252,6 @@ static int get_port_device_capability(struct pci_dev *dev)
> >>           * permission to use AER.
> >>           */
> >>          if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
> >> -           pci_aer_available() &&
> >>              (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
> >>                  services |= PCIE_PORT_SERVICE_DPC;
> >>
> >> --
> >> 2.17.1
> >>
>
> --
> Sathyanarayanan Kuppuswamy
> Linux Kernel Developer