Re: [PATCH v23 4/5] PCI: Fail FLR when config space is inaccessible

[Farhan Ali <alifm@linux.ibm.com>]

On 8/12/2026 3:34 PM, Bjorn Helgaas wrote:
> On Wed, Aug 05, 2026 at 09:55:17AM -0700, Farhan Ali wrote:
>> If a device is in an error state, then it's config space may not be
>> accssible. Add additional check to validate if a device's config space is
>> accessible before doing an FLR reset.
>>
>> Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
>> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>>   drivers/pci/pci.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index e8d7de77241a..9a9d021301c4 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -4384,6 +4384,9 @@ int pcie_flr(struct pci_dev *dev)
>>   {
>>   	int ret;
>>   
>> +	if (!pci_dev_config_accessible(dev, "FLR"))
>> +		return -ENOTTY;
> I'm not really keen on this racy check to begin with (though I know I
> acked it earlier :)), and also a little hesitant about doing it only
> here and not in a more generic place, since several of the reset
> methods are susceptible to the same issue.
>
> But I guess in your use case, FLR is the typical method used and maybe
> we can worry about the others later.

Yeah, I was also hesitant adding it to the other reset methods as I 
don't have hardware to test it. One reason to have the 
pci_dev_config_accessible() function was to be able to use it in other 
reset methods if needed.

Thanks for reviewing and merging the changes!

Thanks

Farhan


>
>>   	if (!pci_wait_for_pending_transaction(dev))
>>   		pci_err(dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
>>   
>> -- 
>> 2.43.0
>>