[PATCH v6 02/12] PCI: liveupdate: Track outgoing preserved PCI devices

[Pranjal Shrivastava]

On Fri, May 22, 2026 at 08:24:00PM +0000, David Matlack wrote:
> Add APIs to allow drivers to notify the PCI core of which devices are
> being preserved across a Live Update for the next kernel, i.e.
> "outgoing" devices.
> 
> Drivers must notify the PCI core when devices are preserved so that the
> PCI core can update its FLB data (struct pci_ser) and track the list of
> outgoing devices. pci_liveupdate_preserve() notifies the PCI core that a
> device must be preserved across Live Update. pci_liveupdate_unpreserve()
> reverses this (cancels the preservation of the device).
> 
> This tracking ensures the PCI core is fully aware of which devices may
> need special handling during shutdown and kexec, and so that it can be
> handed off to the next kernel.
> 
> Signed-off-by: David Matlack <dmatlack at google.com>

[...]

>  
>  /**
>   * struct pci_dev_ser - Serialized state about a single PCI device.
>   *
>   * @domain: The device's PCI domain number (segment).
>   * @bdf: The device's PCI bus, device, and function number.
> - * @padding: Padding to naturally align struct pci_dev_ser.
> + * @refcount: Reference count used by the PCI core to keep track of whether it
> + *            is done using a device's struct pci_dev_ser. The value of the
> + *            refcount is equal to 1 when the struct pci_dev_ser is in use, and
> + *            0 otherwise.

Note to fellow reviewers: This may seem like a bool instead of refcount,
but this is changed in Patch 6. 

Reviewed-by: Pranjal Shrivastava <praan at google.com>

Thanks,
Praan