Re: [PATCH v2] PCI/ERR: Use pcie_aer_is_native() to judge whether OS owns AER

From: Sathyanarayanan Kuppuswamy
Date: Tue Jul 26 2022 - 11:33:59 EST




On 7/25/22 7:05 PM, Zhuo Chen wrote:
> The AER status of the device that reported the error rather than
> the first downstream port is cleared after commit 7d7cbeaba5b7
> ("PCI/ERR: Clear status of the reporting device"). So "a bridge
> may not exist" which commit aa344bc8b727 ("PCI/ERR: Clear AER
> status only when we control AER") referring to is no longer
> existent, and we just use pcie_aer_is_native() in stead of
> "host->native_aer || pcie_ports_native".

IMO, above history is not required to justify using pcie_aer_is_native()
in place of "host->native_aer || pcie_ports_native".

>
> pci_aer_clear_nonfatal_status() already has pcie_aer_is_native(),
> so we move pci_aer_clear_nonfatal_status() out of
> pcie_aer_is_native().

Moving it outside (pcie_aer_is_native()) does not optimize the
code. So I think it is better to leave it inside.

>
> Replace statements that judge whether OS owns AER in
> get_port_device_capability() with pcie_aer_is_native(), which has
> no functional changes.
>
> Signed-off-by: Zhuo Chen <chenzhuo.1@xxxxxxxxxxxxx>
> ---
> v2:
> - Add details and note in commit log
> ---
> drivers/pci/pcie/err.c | 12 ++----------
> drivers/pci/pcie/portdrv_core.c | 3 +--
> 2 files changed, 3 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index 0c5a143025af..28339c741555 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -184,7 +184,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> int type = pci_pcie_type(dev);
> struct pci_dev *bridge;
> pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> - struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>
> /*
> * If the error was detected by a Root Port, Downstream Port, RCEC,
> @@ -237,16 +236,9 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_dbg(bridge, "broadcast resume message\n");
> pci_walk_bridge(bridge, report_resume, &status);
>
> - /*
> - * If we have native control of AER, clear error status in the device
> - * that detected the error. If the platform retained control of AER,
> - * it is responsible for clearing this status. In that case, the
> - * signaling device may not even be visible to the OS.
> - */

The above comment is still applicable. So I think you don't need to remove it.

> - if (host->native_aer || pcie_ports_native) {
> + if (pcie_aer_is_native(dev))
> pcie_clear_device_status(dev);
> - pci_aer_clear_nonfatal_status(dev);
> - }
> + pci_aer_clear_nonfatal_status(dev);
> pci_info(bridge, "device recovery successful\n");
> return status;
>
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 604feeb84ee4..98c18f4a01b2 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -221,8 +221,7 @@ static int get_port_device_capability(struct pci_dev *dev)
> }
>
> #ifdef CONFIG_PCIEAER
> - if (dev->aer_cap && pci_aer_available() &&
> - (pcie_ports_native || host->native_aer)) {
> + if (pcie_aer_is_native(dev) && pci_aer_available()) {
> services |= PCIE_PORT_SERVICE_AER;
>
> /*

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer