migration: Trivial cleanup on JSON writer of vmstate_save()

Two small cleanups in the same section of vmstate_save():

  - Check vmdesc before the "mixed null/non-null data in array" logic, to
  be crystal clear that it's only about the JSON writer, not the vmstate on
  its own in the migration stream.

  - Since we have is_null variable now, use that to replace a check.

Signed-off-by: Peter Xu <peterx@redhat.com>
Tested-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Juraj Marcin <jmarcin@redhat.com>
Link: https://lore.kernel.org/r/20250114230746.3268797-17-peterx@redhat.com
Signed-off-by: Fabiano Rosas <farosas@suse.de>
This commit is contained in:
Peter Xu 2025-01-14 18:07:46 -05:00 committed by Fabiano Rosas
parent 3dde8fdbad
commit a10b37c553

View file

@ -459,6 +459,8 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
}
/*
* This logic only matters when dumping VM Desc.
*
* Due to the fake nullptr handling above, if there's mixed
* null/non-null data, it doesn't make sense to emit a
* compressed array representation spanning the entire array
@ -466,7 +468,7 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
* vs. nullptr). Search ahead for the next null/non-null element
* and start a new compressed array if found.
*/
if (field->flags & VMS_ARRAY_OF_POINTER &&
if (vmdesc && (field->flags & VMS_ARRAY_OF_POINTER) &&
is_null != is_prev_null) {
is_prev_null = is_null;
@ -504,7 +506,7 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
written_bytes);
/* If we used a fake temp field.. free it now */
if (inner_field != field) {
if (is_null) {
g_clear_pointer((gpointer *)&inner_field, g_free);
}