Introduce helper functions vhost_vrings_map() and
vhost_vrings_unmap() and use them.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.s.norwitz@gmail.com>
---
 hw/virtio/vhost.c | 82 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 52 insertions(+), 30 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 52a3236fff..8c5e434b89 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -488,6 +488,53 @@ static void vhost_memory_unmap(struct vhost_dev *dev, void **buffer,
     *buffer = NULL;
 }
 
+static void vhost_vrings_unmap(struct vhost_dev *dev,
+                               struct vhost_virtqueue *vq, bool touched)
+{
+    vhost_memory_unmap(dev, &vq->used, vq->used_size, touched,
+                       touched ? vq->used_size : 0);
+    vhost_memory_unmap(dev, &vq->avail, vq->avail_size, 0,
+                       touched ? vq->avail_size : 0);
+    vhost_memory_unmap(dev, &vq->desc, vq->desc_size, 0,
+                       touched ? vq->desc_size : 0);
+}
+
+static int vhost_vrings_map(struct vhost_dev *dev,
+                            struct VirtIODevice *vdev,
+                            struct vhost_virtqueue *vq,
+                            unsigned idx)
+{
+    vq->desc_phys = virtio_queue_get_desc_addr(vdev, idx);
+    if (vq->desc_phys == 0) {
+        /* Queue might not be ready for start */
+        return 0;
+    }
+    vq->desc_size = virtio_queue_get_desc_size(vdev, idx);
+    vq->desc = vhost_memory_map(dev, vq->desc_phys, vq->desc_size, false);
+    if (!vq->desc) {
+        return -ENOMEM;
+    }
+
+    vq->avail_size = virtio_queue_get_avail_size(vdev, idx);
+    vq->avail_phys = virtio_queue_get_avail_addr(vdev, idx);
+    vq->avail = vhost_memory_map(dev, vq->avail_phys, vq->avail_size, false);
+    if (!vq->avail) {
+        goto fail;
+    }
+
+    vq->used_size = virtio_queue_get_used_size(vdev, idx);
+    vq->used_phys = virtio_queue_get_used_addr(vdev, idx);
+    vq->used = vhost_memory_map(dev, vq->used_phys, vq->used_size, true);
+    if (!vq->used) {
+        goto fail;
+    }
+
+    return 1;
+fail:
+    vhost_vrings_unmap(dev, vq, false);
+    return -ENOMEM;
+}
+
 static int vhost_verify_ring_part_mapping(void *ring_hva,
                                           uint64_t ring_gpa,
                                           uint64_t ring_size,
@@ -1286,30 +1333,9 @@ int vhost_virtqueue_start(struct vhost_dev *dev,
     };
     struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
 
-    vq->desc_phys = virtio_queue_get_desc_addr(vdev, idx);
-    if (vq->desc_phys == 0) {
-        /* Queue might not be ready for start */
-        return 0;
-    }
-    vq->desc_size = virtio_queue_get_desc_size(vdev, idx);
-    vq->desc = vhost_memory_map(dev, vq->desc_phys, vq->desc_size, false);
-    if (!vq->desc) {
-        r = -ENOMEM;
-        goto fail;
-    }
-    vq->avail_size = virtio_queue_get_avail_size(vdev, idx);
-    vq->avail_phys = virtio_queue_get_avail_addr(vdev, idx);
-    vq->avail = vhost_memory_map(dev, vq->avail_phys, vq->avail_size, false);
-    if (!vq->avail) {
-        r = -ENOMEM;
-        goto fail;
-    }
-    vq->used_size = virtio_queue_get_used_size(vdev, idx);
-    vq->used_phys = virtio_queue_get_used_addr(vdev, idx);
-    vq->used = vhost_memory_map(dev, vq->used_phys, vq->used_size, true);
-    if (!vq->used) {
-        r = -ENOMEM;
-        goto fail;
+    r = vhost_vrings_map(dev, vdev, vq, idx);
+    if (r <= 0) {
+        return r;
     }
 
     vq->num = state.num = virtio_queue_get_num(vdev, idx);
@@ -1371,9 +1397,7 @@ int vhost_virtqueue_start(struct vhost_dev *dev,
     return 0;
 
 fail:
-    vhost_memory_unmap(dev, &vq->used, vq->used_size, 0, 0);
-    vhost_memory_unmap(dev, &vq->avail, vq->avail_size, 0, 0);
-    vhost_memory_unmap(dev, &vq->desc, vq->desc_size, 0, 0);
+    vhost_vrings_unmap(dev, vq, false);
     return r;
 }
 
@@ -1420,9 +1444,7 @@ static int do_vhost_virtqueue_stop(struct vhost_dev *dev,
                                                 vhost_vq_index);
     }
 
-    vhost_memory_unmap(dev, &vq->used, vq->used_size, 1, vq->used_size);
-    vhost_memory_unmap(dev, &vq->avail, vq->avail_size, 0, vq->avail_size);
-    vhost_memory_unmap(dev, &vq->desc, vq->desc_size, 0, vq->desc_size);
+    vhost_vrings_unmap(dev, vq, true);
     return r;
 }
 
-- 
2.48.1