• Alex Williamson's avatar
    [IA64] Clear IRQ affinity when unregistered · 451fe00c
    Alex Williamson authored
    When we offline a CPU, migrate_irqs() tries to determine whether the
    affinity bits of the IRQ descriptor match any of the remaining online
    CPUs.  If not, it fixes up the interrupt to point somewhere else.
    Unfortunately, if an IRQ is unregistered the IRQ descriptor may still
    have affinity to the CPU being offlined, but the no_irq_chip handler
    doesn't provide a set_affinity function.  This causes us to hit the
    WARN_ON in migrate_irqs().
    
    The easiest solution seems to be setting all the bits in the affinity
    mask when the last interrupt is removed from the vector.  I hit this on
    an older kernel with Xen/ia64 using driver domains (so it probably needs
    more testing on upstream).  Xen essentially uses the bind/unbind
    interface in sysfs to unregister a device from a driver and thus
    unregister the interrupt.
    Signed-off-by: default avatarAlex Williamson <alex.williamson@hp.com>
    Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
    451fe00c
iosapic.c 30.9 KB