Re: [PATCH v1 3/3] s390/pci: Restore IRQ unconditionally for the zPCI device

[Farhan Ali]

On 10/21/2025 7:07 AM, Matthew Rosato wrote:
> On 10/20/25 3:02 PM, Farhan Ali wrote:
> > Commit c1e18c17bda6 ("s390/pci: add zpci_set_irq()/zpci_clear_irq()"),
> > introduced the zpci_set_irq() and zpci_clear_irq(), to be used while
> > resetting a zPCI device.
> >
> > Commit da995d538d3a ("s390/pci: implement reset_slot for hotplug slot"),
> > mentions zpci_clear_irq() being called in the path for zpci_hot_reset_device().
> > But that is not the case anymore and these functions are not called
> > outside of this file. Instead zpci_hot_reset_device() relies on
> > zpci_disable_device() also clearing the IRQs, but misses to reset the
> > zdev->irqs_registered flag.
> >
> > However after a CLP disable/enable reset, the device's IRQ are
> > unregistered, but the flag zdev->irq_registered does not get cleared. It
> > creates an inconsistent state and so arch_restore_msi_irqs() doesn't
> > correctly restore the device's IRQ. This becomes a problem when a PCI
> > driver tries to restore the state of the device through
> > pci_restore_state(). Restore IRQ unconditionally for the device and remove
> > the irq_registered flag as its redundant.
> >
> > Reviewed-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
> > Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
> Reviewed-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
>
> But one question: Unlike the other 2 patches in this series, this only touches s390 code.  It doesn't depend on the other 2 patches in this series, right?
>
> If not then shouldn't this one go thru s390 rather than PCI subsystem?  Note: none of the s390 arch maintainers are on CC.

Yes I think this could go through s390 tree as it just changes s390/pci 
code. Will submit this as a separate patch from this series.

Thanks

Farhan

> > ---
> >   arch/s390/include/asm/pci.h | 1 -
> >   arch/s390/pci/pci_irq.c     | 9 +--------
> >   2 files changed, 1 insertion(+), 9 deletions(-)