[Qemu-devel] [PATCH 9/9] virtio: remove starting/stopping checks

[Paolo Bonzini]

Reentrancy cannot happen while the BQL is being held.

Reviewed-by: Cornelia Huck <cornelia.h...@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 hw/block/dataplane/virtio-blk.c | 12 ++----------
 hw/scsi/virtio-scsi-dataplane.c |  9 +--------
 include/hw/virtio/virtio-scsi.h |  2 --
 3 files changed, 3 insertions(+), 20 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 74c6d37..cb00cdc 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -27,9 +27,6 @@
 #include "qom/object_interfaces.h"
 
 struct VirtIOBlockDataPlane {
-    bool starting;
-    bool stopping;
-
     VirtIOBlkConf *conf;
 
     VirtIODevice *vdev;
@@ -203,11 +200,10 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
     VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
     int r;
 
-    if (vblk->dataplane_started || s->starting) {
+    if (vblk->dataplane_started) {
         return;
     }
 
-    s->starting = true;
     s->vq = virtio_get_queue(s->vdev, 0);
 
     /* Set up guest notifier (irq) */
@@ -226,7 +222,6 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
         goto fail_host_notifier;
     }
 
-    s->starting = false;
     vblk->dataplane_started = true;
     trace_virtio_blk_data_plane_start(s);
 
@@ -246,7 +241,6 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
     k->set_guest_notifiers(qbus->parent, 1, false);
   fail_guest_notifiers:
     vblk->dataplane_disabled = true;
-    s->starting = false;
     vblk->dataplane_started = true;
 }
 
@@ -257,7 +251,7 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
 
-    if (!vblk->dataplane_started || s->stopping) {
+    if (!vblk->dataplane_started) {
         return;
     }
 
@@ -267,7 +261,6 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
         vblk->dataplane_started = false;
         return;
     }
-    s->stopping = true;
     trace_virtio_blk_data_plane_stop(s);
 
     aio_context_acquire(s->ctx);
@@ -286,5 +279,4 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
     k->set_guest_notifiers(qbus->parent, 1, false);
 
     vblk->dataplane_started = false;
-    s->stopping = false;
 }
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index 5494dcc..7511447 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -115,14 +115,11 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 
     if (s->dataplane_started ||
-        s->dataplane_starting ||
         s->dataplane_fenced ||
         s->ctx != iothread_get_aio_context(vs->conf.iothread)) {
         return;
     }
 
-    s->dataplane_starting = true;
-
     /* Set up guest notifier (irq) */
     rc = k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, true);
     if (rc != 0) {
@@ -150,7 +147,6 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
         }
     }
 
-    s->dataplane_starting = false;
     s->dataplane_started = true;
     aio_context_release(s->ctx);
     return;
@@ -164,7 +160,6 @@ fail_vrings:
     k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false);
 fail_guest_notifiers:
     s->dataplane_fenced = true;
-    s->dataplane_starting = false;
     s->dataplane_started = true;
 }
 
@@ -176,7 +171,7 @@ void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
     int i;
 
-    if (!s->dataplane_started || s->dataplane_stopping) {
+    if (!s->dataplane_started) {
         return;
     }
 
@@ -186,7 +181,6 @@ void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
         s->dataplane_started = false;
         return;
     }
-    s->dataplane_stopping = true;
     assert(s->ctx == iothread_get_aio_context(vs->conf.iothread));
 
     aio_context_acquire(s->ctx);
@@ -203,6 +197,5 @@ void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
 
     /* Clean up guest notifier (irq) */
     k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false);
-    s->dataplane_stopping = false;
     s->dataplane_started = false;
 }
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index ba2f5ce..d5352d8 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -89,8 +89,6 @@ typedef struct VirtIOSCSI {
     QTAILQ_HEAD(, VirtIOSCSIBlkChangeNotifier) remove_notifiers;
 
     bool dataplane_started;
-    bool dataplane_starting;
-    bool dataplane_stopping;
     bool dataplane_fenced;
     Error *blocker;
     uint32_t host_features;
-- 
1.8.3.1