From 4adea8042f880dd9bd7cb5c191a781ec86fdc587 Mon Sep 17 00:00:00 2001
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Date: Wed, 15 Oct 2014 15:15:26 +0200
Subject: [PATCH] virtio-scsi: dataplane: stop trying on notifier error

There's no use to constantly trying to enable dataplane if we failed
to set up guest or host notifiers, so fence it off in that case.
We'll try again if the device is reinitialized.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/virtio-scsi-dataplane.c | 8 ++++++++
 include/hw/virtio/virtio-scsi.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index 243a4765e9..3097d544b4 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -53,6 +53,7 @@ static VirtIOSCSIVring *virtio_scsi_vring_init(VirtIOSCSI *s,
     if (rc != 0) {
         fprintf(stderr, "virtio-scsi: Failed to set host notifier (%d)\n",
                 rc);
+        s->dataplane_fenced = true;
         return NULL;
     }
     r->host_notifier = *virtio_queue_get_host_notifier(vq);
@@ -198,6 +199,7 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
 
     if (s->dataplane_started ||
         s->dataplane_starting ||
+        s->dataplane_fenced ||
         s->ctx != iothread_get_aio_context(vs->conf.iothread)) {
         return;
     }
@@ -211,6 +213,7 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
     if (rc != 0) {
         fprintf(stderr, "virtio-scsi: Failed to set guest notifiers (%d), "
                 "ensure -enable-kvm is set\n", rc);
+        s->dataplane_fenced = true;
         goto fail_guest_notifiers;
     }
 
@@ -262,6 +265,11 @@ void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
     int i;
 
+    /* Better luck next time. */
+    if (s->dataplane_fenced) {
+        s->dataplane_fenced = false;
+        return;
+    }
     if (!s->dataplane_started || s->dataplane_stopping) {
         return;
     }
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 1ce08581ea..9e1a49c2c1 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -195,6 +195,7 @@ typedef struct VirtIOSCSI {
     bool dataplane_starting;
     bool dataplane_stopping;
     bool dataplane_disabled;
+    bool dataplane_fenced;
     Error *blocker;
     Notifier migration_state_notifier;
 } VirtIOSCSI;
-- 
2.11.4.GIT