[PATCH v4 2/5] hw/virtio: document SharedObject structures

[Albert Esteve <aesteve@redhat.com>]

Change VirtioSharedObject value type from
a generic pointer to a union storing the different
supported underlying types, which makes naming
less confusing.

With the update, use the chance to add kdoc
to both the SharedObjectType enum and
VirtioSharedObject struct.

Signed-off-by: Albert Esteve <aesteve@redhat.com>
---
 hw/display/virtio-dmabuf.c        |  8 ++++----
 include/hw/virtio/virtio-dmabuf.h | 25 ++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/hw/display/virtio-dmabuf.c b/hw/display/virtio-dmabuf.c
index 3dba4577ca..497cb6fa7c 100644
--- a/hw/display/virtio-dmabuf.c
+++ b/hw/display/virtio-dmabuf.c
@@ -57,7 +57,7 @@ bool virtio_add_dmabuf(QemuUUID *uuid, int udmabuf_fd)
     }
     vso = g_new(VirtioSharedObject, 1);
     vso->type = TYPE_DMABUF;
-    vso->value = GINT_TO_POINTER(udmabuf_fd);
+    vso->value.udma_buf = udmabuf_fd;
     result = virtio_add_resource(uuid, vso);
     if (!result) {
         g_free(vso);
@@ -75,7 +75,7 @@ bool virtio_add_vhost_device(QemuUUID *uuid, struct vhost_dev *dev)
     }
     vso = g_new(VirtioSharedObject, 1);
     vso->type = TYPE_VHOST_DEV;
-    vso->value = dev;
+    vso->value.dev = dev;
     result = virtio_add_resource(uuid, vso);
     if (!result) {
         g_free(vso);
@@ -114,7 +114,7 @@ int virtio_lookup_dmabuf(const QemuUUID *uuid)
         return -1;
     }
     assert(vso->type == TYPE_DMABUF);
-    return GPOINTER_TO_INT(vso->value);
+    return vso->value.udma_buf;
 }
 
 struct vhost_dev *virtio_lookup_vhost_device(const QemuUUID *uuid)
@@ -124,7 +124,7 @@ struct vhost_dev *virtio_lookup_vhost_device(const QemuUUID *uuid)
         return NULL;
     }
     assert(vso->type == TYPE_VHOST_DEV);
-    return (struct vhost_dev *) vso->value;
+    return (struct vhost_dev *) vso->value.dev;
 }
 
 SharedObjectType virtio_object_type(const QemuUUID *uuid)
diff --git a/include/hw/virtio/virtio-dmabuf.h b/include/hw/virtio/virtio-dmabuf.h
index 627c3b6db7..891a43162d 100644
--- a/include/hw/virtio/virtio-dmabuf.h
+++ b/include/hw/virtio/virtio-dmabuf.h
@@ -16,15 +16,38 @@
 #include "qemu/uuid.h"
 #include "vhost.h"
 
+/**
+ * SharedObjectType:
+ * 
+ * Identifies the type of the underlying type that the current lookup
+ * table entry is holding.
+ * 
+ * TYPE_INVALID: Invalid entry
+ * TYPE_DMABUF: Entry is a dmabuf file descriptor that can be directly
+ *              shared with the requestor
+ * TYPE_VHOST_DEV: Entry is a pointer to a vhost device that is holding
+ *                 the shared object.
+ */
 typedef enum SharedObjectType {
     TYPE_INVALID = 0,
     TYPE_DMABUF,
     TYPE_VHOST_DEV,
 } SharedObjectType;
 
+/**
+ * VirtioSharedObject:
+ * @type: Shared object type identifier
+ * @value: Union containing to the underlying type
+ * 
+ * The VirtioSharedObject object provides a way to distinguish,
+ * store, and handle the different types supported by the lookup table.
+ */
 typedef struct VirtioSharedObject {
     SharedObjectType type;
-    gpointer value;
+    union {
+        struct vhost_dev *dev;  /* TYPE_VHOST_DEV */
+        int udma_buf;           /* TYPE_DMABUF */
+    } value;
 } VirtioSharedObject;
 
 /**
-- 
2.43.1