From c9d1a56174339b0afdef63b7d151b38f4bb6dae5 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 27 Oct 2016 12:49:05 +0200 Subject: block: only call aio_poll on the current thread's AioContext aio_poll is not thread safe; for example bdrv_drain can hang if the last in-flight I/O operation is completed in the I/O thread after the main thread has checked bs->in_flight. The bug remains latent as long as all of it is called within aio_context_acquire/aio_context_release, but this will change soon. To fix this, if bdrv_drain is called from outside the I/O thread, signal the main AioContext through a dummy bottom half. The event loop then only runs in the I/O thread. Reviewed-by: Fam Zheng Signed-off-by: Paolo Bonzini Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng --- hw/scsi/virtio-scsi-dataplane.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'hw/scsi') diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c index b173b94949..9424f0e057 100644 --- a/hw/scsi/virtio-scsi-dataplane.c +++ b/hw/scsi/virtio-scsi-dataplane.c @@ -189,13 +189,11 @@ void virtio_scsi_dataplane_stop(VirtIOSCSI *s) assert(s->ctx == iothread_get_aio_context(vs->conf.iothread)); aio_context_acquire(s->ctx); - virtio_scsi_clear_aio(s); + aio_context_release(s->ctx); blk_drain_all(); /* ensure there are no in-flight requests */ - aio_context_release(s->ctx); - for (i = 0; i < vs->conf.num_queues + 2; i++) { virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); } -- cgit v1.2.3-55-g7522