• Will Deacon's avatar
    ARM: 7406/1: hotplug: copy the affinity mask when forcefully migrating IRQs · 5e7371de
    Will Deacon authored
    When a CPU is hotplugged off, we migrate any IRQs currently affine to it
    away and onto another online CPU by calling the irq_set_affinity
    function of the relevant interrupt controller chip. This function
    returns either IRQ_SET_MASK_OK or IRQ_SET_MASK_OK_NOCOPY, to indicate
    whether irq_data.affinity was updated.
    
    If we are forcefully migrating an interrupt (because the affinity mask
    no longer identifies any online CPUs) then we should update the IRQ
    affinity mask to reflect the new CPU set. Failure to do so can
    potentially leave /proc/irq/n/smp_affinity identifying only offline
    CPUs, which may confuse userspace IRQ balancing daemons.
    
    This patch updates migrate_one_irq to copy the affinity mask when
    the interrupt chip returns IRQ_SET_MASK_OK after forcefully changing the
    affinity of an interrupt.
    
    Cc: stable@vger.kernel.org
    Reported-by: default avatarLeif Lindholm <leif.lindholm@arm.com>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
    5e7371de
irq.c 4.93 KB