Re: [PATCH v2] PCI/AER: Use pci_clear_and_set_config_dword() to simplify mask updates

[Manivannan Sadhasivam]

On Sat, Jun 07, 2025 at 11:51:59PM +0800, Hans Zhang wrote:
> Replace manual read-modify-write sequences in multiple functions with
> pci_clear_and_set_config_dword() to ensure atomic operations and reduce
> code duplication. 
> 

No, pci_clear_and_set_config_dword() doesn't ensure atomicity. It just provides
a helper to avoid code duplication for RMW kind of operations. Nothing
guarantees the function to be atomic.

> Signed-off-by: Hans Zhang <18255117...@163.com>

But the change LGTM. With the above wording corrected,

Acked-by: Manivannan Sadhasivam <m...@kernel.org>

- Mani

> ---
> Changes for v2:
> - The patch commit message were modified.
> - New optimizations for the functions disable_ecrc_checking, aer_enable_irq, 
> and aer_disable_irq have been added.
> ---
>  drivers/pci/pcie/aer.c | 30 +++++++++++-------------------
>  1 file changed, 11 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 70ac66188367..86cbd204a73f 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;
>  }
> @@ -1101,15 +1100,12 @@ 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)
> @@ -1555,23 +1551,19 @@ 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);
>  }
>  
>  /**
> 
> base-commit: ec7714e4947909190ffb3041a03311a975350fe0
> -- 
> 2.25.1
> 

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