• Ross Lagerwall's avatar
    xen/events/fifo: Handle linked events when closing a port · fcdf31a7
    Ross Lagerwall authored
    An event channel bound to a CPU that was offlined may still be linked
    on that CPU's queue.  If this event channel is closed and reused,
    subsequent events will be lost because the event channel is never
    unlinked and thus cannot be linked onto the correct queue.
    
    When a channel is closed and the event is still linked into a queue,
    ensure that it is unlinked before completing.
    
    If the CPU to which the event channel bound is online, spin until the
    event is handled by that CPU. If that CPU is offline, it can't handle
    the event, so clear the event queue during the close, dropping the
    events.
    
    This fixes the missing interrupts (and subsequent disk stalls etc.)
    when offlining a CPU.
    Signed-off-by: default avatarRoss Lagerwall <ross.lagerwall@citrix.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
    fcdf31a7
events_internal.h 3.41 KB