memory_region_transaction_{begin|commit}() could be too big when finalizing a
memory region.  E.g., we should never attempt to update address space topology
during the finalize() of a memory region.  Provide helpers for further use.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 memory.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/memory.c b/memory.c
index 601b749906..e5d634d648 100644
--- a/memory.c
+++ b/memory.c
@@ -1054,10 +1054,20 @@ static void address_space_update_topology(AddressSpace *as)
     address_space_set_flatview(as);
 }
 
+static void memory_region_transaction_push(void)
+{
+    memory_region_transaction_depth++;
+}
+
+static void memory_region_transaction_pop(void)
+{
+    memory_region_transaction_depth--;
+}
+
 void memory_region_transaction_begin(void)
 {
     qemu_flush_coalesced_mmio_buffer();
-    ++memory_region_transaction_depth;
+    memory_region_transaction_push();
 }
 
 void memory_region_transaction_commit(void)
@@ -1067,7 +1077,7 @@ void memory_region_transaction_commit(void)
     assert(memory_region_transaction_depth);
     assert(qemu_mutex_iothread_locked());
 
-    --memory_region_transaction_depth;
+    memory_region_transaction_pop();
     if (!memory_region_transaction_depth) {
         if (memory_region_update_pending) {
             flatviews_reset();
-- 
2.24.1