migration: Use normal VMStateDescriptions for Subsections

We create optional sections with this patch.  But we already have
optional subsections.  Instead of having two mechanism that do the
same, we can just generalize it.

For subsections we just change:

- Add a needed function to VMStateDescription
- Remove VMStateSubsection (after removal of the needed function
  it is just a VMStateDescription)
- Adjust the whole tree, moving the needed function to the corresponding
  VMStateDescription

Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/cpus.c b/cpus.c
index f38b858f9b..b85fb5f03f 100644
--- a/cpus.c
+++ b/cpus.c
@@ -480,6 +480,7 @@ static const VMStateDescription icount_vmstate_timers = {
     .name = "timer/icount",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = icount_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT64(qemu_icount_bias, TimersState),
         VMSTATE_INT64(qemu_icount, TimersState),
@@ -497,13 +498,9 @@ static const VMStateDescription vmstate_timers = {
         VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &icount_vmstate_timers,
-            .needed = icount_state_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &icount_vmstate_timers,
+        NULL
     }
 };