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Date: Thu, 29 Feb 2024 16:26:44 -0600
From: Bjorn Helgaas <helgaas@kernel.org>
To: Ethan Zhao <haifeng.zhao@linux.intel.com>
Cc: baolu.lu@linux.intel.com, bhelgaas@google.com, robin.murphy@arm.com,
	jgg@ziepe.ca, kevin.tian@intel.com, dwmw2@infradead.org,
	will@kernel.org, lukas@wunner.de, yi.l.liu@intel.com,
	dan.carpenter@linaro.org, iommu@lists.linux.dev,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	Haorong Ye <yehaorong@bytedance.com>
Subject: Re: [PATCH v13 1/3] PCI: make pci_dev_is_disconnected() helper
 public for other drivers
Message-ID: <20240229222644.GA367986@bhelgaas>
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In-Reply-To: <20240222090251.2849702-2-haifeng.zhao@linux.intel.com>

On Thu, Feb 22, 2024 at 04:02:49AM -0500, Ethan Zhao wrote:
> Make pci_dev_is_disconnected() public so that it can be called from
> Intel VT-d driver to quickly fix/workaround the surprise removal
> unplug hang issue for those ATS capable devices on PCIe switch downstream
> hotplug capable ports.
> 
> Beside pci_device_is_present() function, this one has no config space
> space access, so is light enough to optimize the normal pure surprise
> removal and safe removal flow.
> 
> Tested-by: Haorong Ye <yehaorong@bytedance.com>
> Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
>  drivers/pci/pci.h   | 5 -----
>  include/linux/pci.h | 5 +++++
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index e9750b1b19ba..bfc56f7bee1c 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -368,11 +368,6 @@ static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
>  	return 0;
>  }
>  
> -static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
> -{
> -	return dev->error_state == pci_channel_io_perm_failure;
> -}
> -
>  /* pci_dev priv_flags */
>  #define PCI_DEV_ADDED 0
>  #define PCI_DPC_RECOVERED 1
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 7ab0d13672da..213109d3c601 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2517,6 +2517,11 @@ static inline struct pci_dev *pcie_find_root_port(struct pci_dev *dev)
>  	return NULL;
>  }
>  
> +static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
> +{
> +	return dev->error_state == pci_channel_io_perm_failure;
> +}
> +
>  void pci_request_acs(void);
>  bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
>  bool pci_acs_path_enabled(struct pci_dev *start,
> -- 
> 2.31.1
>