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

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Message-ID: <b41d1840-b726-2caa-5bc8-69c3aeb230cf@linux.intel.com>
Date:   Tue, 26 Jul 2022 08:33:54 -0700
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Zhuo Chen <chenzhuo.1@...edance.com>, ruscur@...sell.cc,
        oohall@...il.com, bhelgaas@...gle.com
Cc:     lukas@...ner.de, jan.kiszka@...mens.com, stuart.w.hayes@...il.com,
        linuxppc-dev@...ts.ozlabs.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] PCI/ERR: Use pcie_aer_is_native() to judge whether OS
 owns AER



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@...edance.com>
> ---
> 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