From 485e3ce88e8af0e5311dd626f399b3a1e0846dd6 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 13 Mar 2013 15:14:15 +0100 Subject: dataplane: fix hang introduced by AioContext transition The bug is that the EventNotifiers do have a NULL io_flush callback. Because _none_ of the callbacks on the dataplane AioContext have such a callback, aio_poll will simply do nothing. Fixed by adding the callbacks: the ioeventfd will always be polled (this can change in the future to pause/resume the processing during live snapshots or similar operations); the ioqueue will be polled if there are outstanding requests. I must admit I have screwed up my testing somehow, because commit 2c20e71 does not work even if cherry-picked on top of 1.4.0, and this patch fixes it there as well. Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- hw/dataplane/virtio-blk.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/hw/dataplane/virtio-blk.c b/hw/dataplane/virtio-blk.c index dfe5f9b..1242d61 100644 --- a/hw/dataplane/virtio-blk.c +++ b/hw/dataplane/virtio-blk.c @@ -263,6 +263,11 @@ static int process_request(IOQueue *ioq, struct iovec iov[], } } +static int flush_true(EventNotifier *e) +{ + return true; +} + static void handle_notify(EventNotifier *e) { VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane, @@ -342,6 +347,14 @@ static void handle_notify(EventNotifier *e) } } +static int flush_io(EventNotifier *e) +{ + VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane, + io_notifier); + + return s->num_reqs > 0; +} + static void handle_io(EventNotifier *e) { VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane, @@ -472,7 +485,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) exit(1); } s->host_notifier = *virtio_queue_get_host_notifier(vq); - aio_set_event_notifier(s->ctx, &s->host_notifier, handle_notify, NULL); + aio_set_event_notifier(s->ctx, &s->host_notifier, handle_notify, flush_true); /* Set up ioqueue */ ioq_init(&s->ioqueue, s->fd, REQ_MAX); @@ -480,7 +493,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) ioq_put_iocb(&s->ioqueue, &s->requests[i].iocb); } s->io_notifier = *ioq_get_notifier(&s->ioqueue); - aio_set_event_notifier(s->ctx, &s->io_notifier, handle_io, NULL); + aio_set_event_notifier(s->ctx, &s->io_notifier, handle_io, flush_io); s->started = true; trace_virtio_blk_data_plane_start(s); -- cgit v1.1