linux-kernel - Re: [PATCH v3] PCI/AER: Use pci_clear_and_set_config

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Message-ID: <c965d655-8423-435b-ade7-6bd02e5989b0@163.com>
Date: Sun, 17 Aug 2025 23:07:44 +0800
From: Hans Zhang <18255117159@....com>
To: Lukas Wunner <lukas@...ner.de>
Cc: mahesh@...ux.ibm.com, bhelgaas@...gle.com, oohall@...il.com,
 mani@...nel.org, linuxppc-dev@...ts.ozlabs.org, linux-pci@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] PCI/AER: Use pci_clear_and_set_config_dword() to
 simplify mask updates



On 2025/8/17 04:25, Lukas Wunner wrote:
> On Sun, Aug 17, 2025 at 12:17:43AM +0800, Hans Zhang wrote:
>> Replace manual read-modify-write sequences in multiple functions with
>> pci_clear_and_set_config_dword() helper to reduce code duplication.
> 
> None of the occurrences you're replacing is clearing *and* setting
> bits at the same time.  They all either clear or set bits, but not both.
> 
> For the PCIe Capability, there are pcie_capability_clear_dword()
> and pcie_capability_set_dword() helpers.
> 
> It would arguably be clearer and less confusing to introduce similar
> pci_clear_config_dword() and pci_set_config_dword() helpers and use
> those, instead of using pci_clear_and_set_config_dword() and setting
> one argument to 0.
> 

Dear Lukas,

Thank you very much for your reply and suggestions.

In the next version, I will introduce two helper functions, 
pci_clear_config_dword() and pci_set_config_dword().

Best regards,
Hans


> Thanks,
> 
> Lukas
> 
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index e286c197d716..3d37e2b7e412 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -176,14 +176,13 @@ static int enable_ecrc_checking(struct pci_dev *dev)
>>   static int disable_ecrc_checking(struct pci_dev *dev)
>>   {
>>   	int aer = dev->aer_cap;
>> -	u32 reg32;
>>   
>>   	if (!aer)
>>   		return -ENODEV;
>>   
>> -	pci_read_config_dword(dev, aer + PCI_ERR_CAP, &reg32);
>> -	reg32 &= ~(PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE);
>> -	pci_write_config_dword(dev, aer + PCI_ERR_CAP, reg32);
>> +	pci_clear_and_set_config_dword(dev, aer + PCI_ERR_CAP,
>> +				       PCI_ERR_CAP_ECRC_GENE |
>> +				       PCI_ERR_CAP_ECRC_CHKE, 0);
>>   
>>   	return 0;
>>   }
>> @@ -1102,15 +1101,12 @@ static bool find_source_device(struct pci_dev *parent,
>>   static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>>   {
>>   	int aer = dev->aer_cap;
>> -	u32 mask;
>>   
>> -	pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_MASK, &mask);
>> -	mask &= ~PCI_ERR_UNC_INTN;
>> -	pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_MASK, mask);
>> +	pci_clear_and_set_config_dword(dev, aer + PCI_ERR_UNCOR_MASK,
>> +				       PCI_ERR_UNC_INTN, 0);
>>   
>> -	pci_read_config_dword(dev, aer + PCI_ERR_COR_MASK, &mask);
>> -	mask &= ~PCI_ERR_COR_INTERNAL;
>> -	pci_write_config_dword(dev, aer + PCI_ERR_COR_MASK, mask);
>> +	pci_clear_and_set_config_dword(dev, aer + PCI_ERR_COR_MASK,
>> +				       PCI_ERR_COR_INTERNAL, 0);
>>   }
>>   
>>   static bool is_cxl_mem_dev(struct pci_dev *dev)
>> @@ -1556,23 +1552,19 @@ static irqreturn_t aer_irq(int irq, void *context)
>>   static void aer_enable_irq(struct pci_dev *pdev)
>>   {
>>   	int aer = pdev->aer_cap;
>> -	u32 reg32;
>>   
>>   	/* Enable Root Port's interrupt in response to error messages */
>> -	pci_read_config_dword(pdev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
>> -	reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
>> -	pci_write_config_dword(pdev, aer + PCI_ERR_ROOT_COMMAND, reg32);
>> +	pci_clear_and_set_config_dword(pdev, aer + PCI_ERR_ROOT_COMMAND,
>> +				       0, ROOT_PORT_INTR_ON_MESG_MASK);
>>   }
>>   
>>   static void aer_disable_irq(struct pci_dev *pdev)
>>   {
>>   	int aer = pdev->aer_cap;
>> -	u32 reg32;
>>   
>>   	/* Disable Root Port's interrupt in response to error messages */
>> -	pci_read_config_dword(pdev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
>> -	reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
>> -	pci_write_config_dword(pdev, aer + PCI_ERR_ROOT_COMMAND, reg32);
>> +	pci_clear_and_set_config_dword(pdev, aer + PCI_ERR_ROOT_COMMAND,
>> +				       ROOT_PORT_INTR_ON_MESG_MASK, 0);
>>   }
>>   
>>   /**