A memory region may not have an owner, and memory_region_ref() and
memory_region_unref() do nothing for such.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 include/exec/memory.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 461e42d03491..d79415a3b159 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1219,7 +1219,7 @@ void memory_region_init(MemoryRegion *mr,
 /**
  * memory_region_ref: Add a reference to a memory region
  *
- * This function adds a reference to the owner.
+ * This function adds a reference to the owner if present.
  * See docs/devel/memory.rst to know about owner.
  *
  * @mr: the #MemoryRegion
@@ -1229,8 +1229,8 @@ void memory_region_ref(MemoryRegion *mr);
 /**
  * memory_region_unref: Remove a reference to a memory region
  *
- * This function removes a reference to the owner and possibly destroys it.
- * See docs/devel/memory.rst to know about owner.
+ * This function removes a reference to the owner and possibly destroys it if
+ * present. See docs/devel/memory.rst to know about owner.
  *
  * @mr: the #MemoryRegion
  */

-- 
2.46.0