blockdev: qmp_transaction: refactor loop to classic for

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230510150624.310640-4-vsementsov@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev.c

@@ -2377,7 +2377,7 @@ void qmp_transaction(TransactionActionList *actions,
                      struct TransactionProperties *properties,
                      Error **errp)
 {
-    TransactionActionList *act = actions;
+    TransactionActionList *act;
     bool has_properties = !!properties;
     JobTxn *block_job_txn = NULL;
     Error *local_err = NULL;
@@ -2397,14 +2397,11 @@ void qmp_transaction(TransactionActionList *actions,
     bdrv_drain_all();
 
     /* We don't do anything in this loop that commits us to the operations */
-    while (NULL != act) {
-        TransactionAction *dev_info = NULL;
+    for (act = actions; act; act = act->next) {
+        TransactionAction *dev_info = act->value;
         const BlkActionOps *ops;
         BlkActionState *state;
 
-        dev_info = act->value;
-        act = act->next;
-
         assert(dev_info->type < ARRAY_SIZE(actions_map));
 
         ops = &actions_map[dev_info->type];