From: Jeremy Fitzhardinge <[email protected]> commit dffe2e1e1a1ddb566a76266136c312801c66dcf7 upstream.
Xen events are logically edge triggered, as Xen only calls the event upcall when an event is newly set, but not continuously as it remains set. As a result, use handle_edge_irq rather than handle_level_irq. This has the important side-effect of fixing a long-standing bug of events getting lost if: - an event's interrupt handler is running - the event is migrated to a different vcpu - the event is re-triggered The most noticable symptom of these lost events is occasional lockups of blkfront. Many thanks to Tom Kopec and Daniel Stodden in tracking this down. Signed-off-by: Jeremy Fitzhardinge <[email protected]> Cc: Tom Kopec <[email protected]> Cc: Daniel Stodden <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> --- drivers/xen/events.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 28f133a..cc72dad 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -363,7 +363,7 @@ int bind_evtchn_to_irq(unsigned int evtchn) irq = find_unbound_irq(); set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, - handle_level_irq, "event"); + handle_edge_irq, "event"); evtchn_to_irq[evtchn] = irq; irq_info[irq] = mk_evtchn_info(evtchn); -- 1.7.3.3 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
