linux-kernel - Re: [PATCH] ntb: idt: drop redundant pci_enable_pcie_error

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Message-ID: <20230309120115.fbcjqtbm7fxvlojg@mobilestation>
Date:   Thu, 9 Mar 2023 15:01:15 +0300
From:   Serge Semin <fancer.lancer@...il.com>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Jon Mason <jdmason@...zu.us>, Dave Jiang <dave.jiang@...el.com>,
        Allen Hubbe <allenbh@...il.com>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>, ntb@...ts.linux.dev,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH] ntb: idt: drop redundant
 pci_enable_pcie_error_reporting()

Hi Bjorn,

On Tue, Mar 07, 2023 at 02:30:21PM -0600, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@...gle.com>
> 
> pci_enable_pcie_error_reporting() enables the device to send ERR_*
> Messages.  Since f26e58bf6f54 ("PCI/AER: Enable error reporting when AER is
> native"), the PCI core does this for all devices during enumeration, so the
> driver doesn't need to do it itself.
> 
> Remove the redundant pci_enable_pcie_error_reporting() call from the
> driver.  Also remove the corresponding pci_disable_pcie_error_reporting()
> from the driver .remove() path.
> 
> Note that this only controls ERR_* Messages from the device.  An ERR_*
> Message may cause the Root Port to generate an interrupt, depending on the
> AER Root Error Command register managed by the AER service driver.

Thanks for the patch.
Acked-by: Serge Semin <fancer.lancer@...il.com>

BTW seeing the pci_aer_init() method fully clears the AER status don't
you think the pci_aer_clear_nonfatal_status() function invocation
should be dropped as well?

Note the patchset doing that was already submitted a while ago:
https://lore.kernel.org/linux-pci/20220928105946.12469-1-chenzhuo.1@bytedance.com
* particular patch:
https://lore.kernel.org/linux-pci/20220928105946.12469-4-chenzhuo.1@bytedance.com

-Serge(y)

> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> ---
>  drivers/ntb/hw/idt/ntb_hw_idt.c | 17 +++++------------
>  1 file changed, 5 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
> index 0ed6f809ff2e..7192ff59dd91 100644
> --- a/drivers/ntb/hw/idt/ntb_hw_idt.c
> +++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
> @@ -2651,20 +2651,18 @@ static int idt_init_pci(struct idt_ntb_dev *ndev)
>  	}
>  
>  	/*
> -	 * Enable the device advanced error reporting. It's not critical to
> +	 * The PCI core enables device error reporting. It's not critical to
>  	 * have AER disabled in the kernel.
> +	 *
> +	 * Cleanup nonfatal error status before getting to init.
>  	 */
> -	ret = pci_enable_pcie_error_reporting(pdev);
> -	if (ret != 0)
> -		dev_warn(&pdev->dev, "PCIe AER capability disabled\n");
> -	else /* Cleanup nonfatal error status before getting to init */
> -		pci_aer_clear_nonfatal_status(pdev);
> +	pci_aer_clear_nonfatal_status(pdev);
>  
>  	/* First enable the PCI device */
>  	ret = pcim_enable_device(pdev);
>  	if (ret != 0) {
>  		dev_err(&pdev->dev, "Failed to enable PCIe device\n");
> -		goto err_disable_aer;
> +		return ret;
>  	}
>  
>  	/*
> @@ -2692,8 +2690,6 @@ static int idt_init_pci(struct idt_ntb_dev *ndev)
>  
>  err_clear_master:
>  	pci_clear_master(pdev);
> -err_disable_aer:
> -	(void)pci_disable_pcie_error_reporting(pdev);
>  
>  	return ret;
>  }
> @@ -2714,9 +2710,6 @@ static void idt_deinit_pci(struct idt_ntb_dev *ndev)
>  	/* Clear the bus master disabling the Request TLPs translation */
>  	pci_clear_master(pdev);
>  
> -	/* Disable the AER capability */
> -	(void)pci_disable_pcie_error_reporting(pdev);
> -
>  	dev_dbg(&pdev->dev, "NT-function PCIe interface cleared");
>  }
>  
> -- 
> 2.25.1
>