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From: Lukas Wunner <lukas@wunner.de>
To: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Konstantin Khlebnikov <khlebnikov@openvz.org>,
	Khalid Aziz <khalid.aziz@oracle.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	oohall@gmail.com, rafael.j.wysocki@intel.com,
	Xuefeng Li <lixuefeng@loongson.cn>,
	Huacai Chen <chenhc@lemote.com>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
Date: Mon, 14 Sep 2020 06:06:25 +0200	[thread overview]
Message-ID: <20200914040625.GA20033@wunner.de> (raw)
In-Reply-To: <1600028950-10644-1-git-send-email-yangtiezhu@loongson.cn>

On Mon, Sep 14, 2020 at 04:29:10AM +0800, Tiezhu Yang wrote:
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -143,6 +144,28 @@ 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);
> +
> +	/*
> +	 * If this is a kexec reboot, turn off Bus Master bit on the
> +	 * device to tell it to not continue to do DMA. Don't touch
> +	 * devices in D3cold or unknown states.
> +	 * If it is not a kexec reboot, firmware will hit the PCI
> +	 * devices with big hammer and stop their DMA any way.
> +	 */
> +	if (kexec_in_progress && (dev->current_state <= PCI_D3hot))
> +		pci_disable_device(dev);

The last portion of this function is already executed afterwards by
pci_device_shutdown().  You don't need to duplicate it here:

device_shutdown()
  dev->bus->shutdown() == pci_device_shutdown()
    drv->shutdown() == pcie_portdrv_shutdown()
      pci_disable_device()
    pci_disable_device()

Thanks,

Lukas

  reply	other threads:[~2020-09-14  4:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-13 20:29 Tiezhu Yang
2020-09-14  4:06 ` Lukas Wunner [this message]
2020-09-14  6:13   ` Tiezhu Yang
2020-09-14  6:30     ` Tiezhu Yang
     [not found] ` <tencent_44F0201A70619BA613F16BA4@qq.com>
2020-09-14  4:31   ` Huacai Chen
2020-09-14  6:17     ` Tiezhu Yang

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