Re: [PATCH 1/1] PCI/ACPI: Remove Hyper-V special case in pcibios_root_bridge_prepare()

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Sep 29, 2026 at 11:10:56AM -0700, Michael Kelley wrote:
> pcibios_root_bridge_prepare() currently has code to handle Hyper-V
> guest root bridges with the sysdata parent field set to NULL. While
> this special case existed when commit 7d40c0f70d92 ("arm64: PCI:
> Support root bridge preparation for Hyper-V") was accepted, more
> recent commit 8d21732475c6 ("PCI: hv: Propagate coherence from VMbus
> device to PCI device") always sets the sysdata parent field to a
> non-NULL value.
> 
> No harm is caused by leaving the special case in place, even
> though it is no longer needed. But in the interest of overall
> code cleanliness, remove it.
> 
> Signed-off-by: Michael Kelley <mhklinux@outlook.com>

Applied to pci/pending/controller/hv for v7.5, thanks!  The branch
will be renamed and rebased to v7.4-rc1 after that is tagged.

> ---
> This patch does not just do a revert of 7d40c0f70d92 because
> an intervening commit moved the code to a new source code
> file.
> 
>  drivers/pci/pci-acpi.c | 12 +-----------
>  1 file changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index 42d545edd7fa..452a90317c58 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -1572,17 +1572,7 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
>  		return 0;
>  
>  	cfg = bridge->bus->sysdata;
> -
> -	/*
> -	 * On Hyper-V there is no corresponding ACPI device for a root bridge,
> -	 * therefore ->parent is set as NULL by the driver. And set 'adev' as
> -	 * NULL in this case because there is no proper ACPI device.
> -	 */
> -	if (!cfg->parent)
> -		adev = NULL;
> -	else
> -		adev = to_acpi_device(cfg->parent);
> -
> +	adev = to_acpi_device(cfg->parent);
>  	bus_dev = &bridge->bus->dev;
>  
>  	ACPI_COMPANION_SET(&bridge->dev, adev);
> -- 
> 2.25.1
>