linux-kernel - Re: [PATCH v3] PCI/ERR: Use pcie_aer_is_native() to judge whether OS owns AER

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Message-ID: <cfd44d9c-453b-e498-2630-9057947cf3cd@bytedance.com>
Date:   Wed, 27 Jul 2022 13:35:56 +0800
From:   陈卓 <chenzhuo.1@...edance.com>
To:     Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.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 v3] PCI/ERR: Use pcie_aer_is_native() to judge whether OS
 owns AER


On 7/26/22 9:02 PM, Sathyanarayanan Kuppuswamy wrote:
> 
> 
> On 7/26/22 8:53 PM, Zhuo Chen wrote:
>> Use pcie_aer_is_native() in place of "host->native_aer ||
>> pcie_ports_native" to judge whether OS has native control of AER
>> in pcie_do_recovery().
>>
>> Replace "dev->aer_cap && (pcie_ports_native || host->native_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>
>> ---
> 
> Patch looks better now. It looks like following two changes
> can also be replaced with pcie_aer_is_native() check.
> 
> drivers/pci/pcie/aer.c:1407:	if ((host->native_aer || pcie_ports_native) && aer) {
> drivers/pci/pcie/aer.c:1426:	if ((host->native_aer || pcie_ports_native) && aer) {

Good advice. But I wonder is there a scenario that dev->rcec ("root") is 
NULL meanwhile dev->aer_cap is not NULL? If so, replace 
"(host->native_aer || pcie_ports_native) && aer" with 
pcie_aer_is_native() will change original function.

> 
> 
> 
>> Changelog:
>> v3:
>> - Simplify why we use pcie_aer_is_native().
>> - Revert modification of pci_aer_clear_nonfatal_status() and comments.
>> v2:
>> - Add details and note in commit log.
>> ---
>>   drivers/pci/pcie/err.c          | 3 +--
>>   drivers/pci/pcie/portdrv_core.c | 3 +--
>>   2 files changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>> index 0c5a143025af..121a53338e44 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,
>> @@ -243,7 +242,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>>   	 * it is responsible for clearing this status.  In that case, the
>>   	 * signaling device may not even be visible to the OS.
>>   	 */
>> -	if (host->native_aer || pcie_ports_native) {
>> +	if (pcie_aer_is_native(dev)) {
>>   		pcie_clear_device_status(dev);
>>   		pci_aer_clear_nonfatal_status(dev);
>>   	}
>> 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;
>>   
>>   		/*
> 

Thanks,
Zhuo Chen