linux-kernel - Re: [RFC PATCH] PCI/portdrv: No need to call pci_disable

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Date:   Thu, 10 Sep 2020 14:41:38 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Xuefeng Li <lixuefeng@...ngson.cn>
Subject: Re: [RFC PATCH] PCI/portdrv: No need to call pci_disable_device()
 during shutdown

On Sat, Sep 05, 2020 at 04:33:26PM +0800, Tiezhu Yang wrote:
> After commit 745be2e700cd ("PCIe: portdrv: call pci_disable_device
> during remove") and commit cc27b735ad3a ("PCI/portdrv: Turn off PCIe
> services during shutdown"), it also calls pci_disable_device() during
> shutdown, this seems unnecessary, so just remove it.

I would like to get rid of the portdrv completely by folding its
functionality into the PCI core itself, so there would be no portdrv
probe or remove.

Does this solve a problem?  If not, I'm inclined to just leave it
as-is for now.  But if it fixes something, we should do the fix, of
course.

> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> ---
>  drivers/pci/pcie/portdrv_core.c |  1 -
>  drivers/pci/pcie/portdrv_pci.c  | 14 +++++++++++++-
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 50a9522..1991aca 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -491,7 +491,6 @@ void pcie_port_device_remove(struct pci_dev *dev)
>  {
>  	device_for_each_child(&dev->dev, NULL, remove_iter);
>  	pci_free_irq_vectors(dev);
> -	pci_disable_device(dev);
>  }
>  
>  /**
> diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
> index 3a3ce40..cab37a8 100644
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -143,6 +143,18 @@ static void pcie_portdrv_remove(struct pci_dev *dev)
>  	}
>  
>  	pcie_port_device_remove(dev);
> +	pci_disable_device(dev);
> +}
> +
> +static void pcie_portdrv_shutdown(struct pci_dev *dev)
> +{
> +	if (pci_bridge_d3_possible(dev)) {
> +		pm_runtime_forbid(&dev->dev);
> +		pm_runtime_get_noresume(&dev->dev);
> +		pm_runtime_dont_use_autosuspend(&dev->dev);
> +	}
> +
> +	pcie_port_device_remove(dev);
>  }
>  
>  static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
> @@ -211,7 +223,7 @@ static struct pci_driver pcie_portdriver = {
>  
>  	.probe		= pcie_portdrv_probe,
>  	.remove		= pcie_portdrv_remove,
> -	.shutdown	= pcie_portdrv_remove,
> +	.shutdown	= pcie_portdrv_shutdown,
>  
>  	.err_handler	= &pcie_portdrv_err_handler,
>  
> -- 
> 2.1.0
>