On 2026-09-17 03:17 PM, Bjorn Helgaas wrote: > On Tue, Jul 28, 2026 at 10:10:04PM +0000, David Matlack wrote: > > Freeze a device's outgoing preservation status (preserved or not > > preserved) during shutdown. This enables the PCI core and drivers to > > safely make decisions based on the device's preservation status during > > shutdown. > > > > Note that pci_liveupdate_freeze() is triggered by the PCI core rather > > than from drivers participating in Live Update so that all devices can > > have their status frozen (i.e. prevent non-preserved devices from > > getting preserved late). > > This calls pci_liveupdate_freeze() from pci_device_shutdown(), the > pci_bus_type .shutdown() method, which I think is only called from > device_shutdown() in the kexec or restart paths. > > Since there's no error exit after we get as far as device_shutdown(), > and this applies to all devices and dev->liveupdate.frozen is never > set to false (at least at this point in the series), is there benefit > to tracking this per-device?
I think this could be global. But I don't see any obvious place to add that hook and keeping it per device is one less global variable to worry about. > > Reviewed-by: Pranjal Shrivastava <[email protected]> > > Reviewed-by: Pasha Tatashin <[email protected]> > > Signed-off-by: David Matlack <[email protected]> > > Reviewed-by: Bjorn Helgaas <[email protected]> > > > --- > > drivers/pci/liveupdate.c | 16 ++++++++++++++++ > > drivers/pci/liveupdate.h | 4 ++++ > > drivers/pci/pci-driver.c | 2 ++ > > include/linux/pci_liveupdate.h | 3 +++ > > 4 files changed, 25 insertions(+) > > > > diff --git a/drivers/pci/liveupdate.c b/drivers/pci/liveupdate.c > > index 744513ee11ed..65bcecb1b64e 100644 > > --- a/drivers/pci/liveupdate.c > > +++ b/drivers/pci/liveupdate.c > > @@ -394,6 +394,11 @@ static int pci_liveupdate_unpreserve_device(struct > > pci_flb_outgoing *outgoing, > > { > > struct pci_dev_ser *dev_ser = dev->liveupdate.outgoing; > > > > + if (dev->liveupdate.frozen) { > > + pci_warn(dev, "Cannot unpreserve device after it is frozen!\n"); > > + return -EINVAL; > > + } > > + > > if (!dev_ser) { > > pci_warn(dev, "Cannot unpreserve device that is not > > preserved\n"); > > return -EINVAL; > > @@ -447,6 +452,11 @@ static int pci_liveupdate_preserve_device(struct > > pci_flb_outgoing *outgoing, > > return -EINVAL; > > } > > > > + if (dev->liveupdate.frozen) { > > + pci_warn(dev, "Cannot preserve device after it is frozen!\n"); > > + return -EINVAL; > > + } > > + > > if (dev->liveupdate.outgoing) { > > if (!dev->liveupdate.outgoing->refcount) { > > pci_WARN(dev, 1, "Preserved device with 0 refcount!\n"); > > @@ -718,6 +728,12 @@ void pci_liveupdate_cleanup_device(struct pci_dev *dev) > > pci_WARN(dev, 1, "Destroying incoming-preserved device!\n"); > > } > > > > +void pci_liveupdate_freeze(struct pci_dev *dev) > > +{ > > + guard(rwsem_write)(&pci_liveupdate.rwsem); > > + dev->liveupdate.frozen = 1; > > Nit, the series assigns "true" to other booleans > (preserve_bus_numbers, was_preserved). Ack, will fix.
