linux-kernel - Re: [RESEND v13 23/25] CXL/PCI: Introduce CXL uncorrectable protocol error recovery

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Message-ID: <3024ae89-4c19-4d29-aca4-0aef21bcd5e9@intel.com>
Date: Wed, 5 Nov 2025 09:10:37 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: "Bowman, Terry" <terry.bowman@....com>,
 Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: dave@...olabs.net, alison.schofield@...el.com, dan.j.williams@...el.com,
 bhelgaas@...gle.com, shiju.jose@...wei.com, ming.li@...omail.com,
 Smita.KoralahalliChannabasappa@....com, rrichter@....com,
 dan.carpenter@...aro.org, PradeepVineshReddy.Kodamati@....com,
 lukas@...ner.de, Benjamin.Cheatham@....com,
 sathyanarayanan.kuppuswamy@...ux.intel.com, linux-cxl@...r.kernel.org,
 alucerop@....com, ira.weiny@...el.com, linux-kernel@...r.kernel.org,
 linux-pci@...r.kernel.org
Subject: Re: [RESEND v13 23/25] CXL/PCI: Introduce CXL uncorrectable protocol
 error recovery



On 11/5/25 7:59 AM, Bowman, Terry wrote:
> 
> 
> On 11/4/2025 5:43 PM, Dave Jiang wrote:
>>
>> On 11/4/25 11:47 AM, Jonathan Cameron wrote:
>>> On Tue, 4 Nov 2025 11:03:03 -0600
>>> Terry Bowman <terry.bowman@....com> wrote:

<snip>

>>>> diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
>>>> index 5bc144cde0ee..52c6f19564b6 100644
>>>> --- a/drivers/cxl/core/ras.c
>>>> +++ b/drivers/cxl/core/ras.c
>>>> @@ -259,8 +259,138 @@ static void device_unlock_if(struct device *dev, bool take)
>>>>  		device_unlock(dev);
>>>>  }
>>>>  
>>>> +/**
>>>> + * cxl_report_error_detected
>>>> + * @dev: Device being reported
>>>> + * @data: Result
>>>> + * @err_pdev: Device with initial detected error. Is locked immediately
>>>> + *            after KFIFO dequeue.
>>>> + */
>>>> +static int cxl_report_error_detected(struct device *dev, void *data, struct pci_dev *err_pdev)
>>>> +{
>>>> +	bool need_lock = (dev != &err_pdev->dev);
>>> Add a comment on why this controls need for locking.
>>> The resulting code is complex enough I'd be tempted to split the whole
>>> thing into locked and unlocked variants.
>> May not be a bad idea. Terry, can you see if this would reduce the complexity?
>>
>> DJ 
> 
> I agree and will split into 2 functions. Do you have naming suggestions for a function copy 
> without locks? Is cxl_report_error_detected_nolock() OK to go along with existing 
> cxl_report_error_detected()? 

Maybe cxl_report_error_detected_lock() vs cxl_report_error_detected().
I think there's also precedent of __cxl_report_error_detected() with no lock and indicates a raw function vs cxl_report_error_detected() with lock. 

DJ

> 
> Terry