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

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

[Michael Kelley]

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>
---
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

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

[Rafael J. Wysocki (Intel)]

On Tue, Sep 29, 2026 at 8:11 PM Michael Kelley <mhkelley58@gmail.com> 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>

Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>

> ---
> 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
>