Re: [PATCH v3] PCI/AER: Use pci_clear_and_set_config_dword() to simplify mask updates

[Hans Zhang]

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);
> >   }
> >   
> >   /**