[PATCH 09/22] vhost: Add opaque member to SVQElement

["Eugenio Pérez" <eperezma@redhat.com>]

When qemu injects buffers to the vdpa device it will be used to maintain
contextual data. If SVQ has no operation, it will be used to maintain
the VirtQueueElement pointer.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h |  3 ++-
 hw/virtio/vhost-shadow-virtqueue.c | 13 +++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index 5646d875cb..3e1bea12ca 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -16,7 +16,8 @@
 #include "hw/virtio/vhost-iova-tree.h"
 
 typedef struct SVQElement {
-    VirtQueueElement *elem;
+    /* Opaque data */
+    void *opaque;
 
     /* Last descriptor of the chain */
     uint32_t last_chain_id;
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 635b6b359f..01caa5887e 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -236,7 +236,7 @@ static uint16_t vhost_svq_last_desc_of_chain(const VhostShadowVirtqueue *svq,
  */
 static bool vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
                           size_t out_num, const struct iovec *in_sg,
-                          size_t in_num, VirtQueueElement *elem)
+                          size_t in_num, void *opaque)
 {
     SVQElement *svq_elem;
     unsigned qemu_head;
@@ -244,13 +244,12 @@ static bool vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
     bool ok = vhost_svq_add_split(svq, out_sg, out_num, in_sg, in_num,
                                   &qemu_head);
     if (unlikely(!ok)) {
-        g_free(elem);
         return false;
     }
 
     n = out_num + in_num;
     svq_elem = &svq->ring_id_maps[qemu_head];
-    svq_elem->elem = elem;
+    svq_elem->opaque = opaque;
     svq_elem->last_chain_id = vhost_svq_last_desc_of_chain(svq, n, qemu_head);
     return true;
 }
@@ -276,6 +275,8 @@ static bool vhost_svq_add_element(VhostShadowVirtqueue *svq,
                             elem->in_num, elem);
     if (ok) {
         vhost_svq_kick(svq);
+    } else {
+        g_free(elem);
     }
 
     return ok;
@@ -391,7 +392,7 @@ static void vhost_svq_disable_notification(VhostShadowVirtqueue *svq)
 
 static bool vhost_svq_is_empty_elem(SVQElement elem)
 {
-    return elem.elem == NULL;
+    return elem.opaque == NULL;
 }
 
 static SVQElement vhost_svq_empty_elem(void)
@@ -466,7 +467,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq,
                 break;
             }
 
-            elem = g_steal_pointer(&svq_elem.elem);
+            elem = g_steal_pointer(&svq_elem.opaque);
             virtqueue_fill(vq, elem, len, i++);
         }
 
@@ -634,7 +635,7 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
 
     for (unsigned i = 0; i < svq->vring.num; ++i) {
         g_autofree VirtQueueElement *elem = NULL;
-        elem = g_steal_pointer(&svq->ring_id_maps[i].elem);
+        elem = g_steal_pointer(&svq->ring_id_maps[i].opaque);
         if (elem) {
             virtqueue_detach_element(svq->vq, elem, 0);
         }
-- 
2.31.1