diff --git a/lib/dbi/path.c b/lib/dbi/path.c
index c15c0f0e7..3d223f44a 100644
--- a/lib/dbi/path.c
+++ b/lib/dbi/path.c
@@ -31,7 +31,7 @@ int ogs_dbi_process_change_stream(const bson_t *document)
     rv = ogs_queue_push(ogs_app()->queue, e);
     if (rv != OGS_OK) {
         ogs_error("ogs_queue_push() failed:%d", (int)rv);
-        bson_destroy((bson_t*)e->dbi.document);
+        bson_destroy(e->dbi.document);
         ogs_event_free(e);
     } else {
         ogs_pollset_notify(ogs_app()->pollset);
diff --git a/lib/proto/event.h b/lib/proto/event.h
index 89624a9ad..da92e0f57 100644
--- a/lib/proto/event.h
+++ b/lib/proto/event.h
@@ -50,8 +50,6 @@ typedef struct ogs_sbi_request_s ogs_sbi_request_t;
 typedef struct ogs_sbi_response_s ogs_sbi_response_t;
 typedef struct ogs_sbi_message_s ogs_sbi_message_t;
 
-typedef struct _bson_t bson_t;
-
 typedef struct ogs_event_s {
     int id;
     int timer_id;
@@ -66,7 +64,7 @@ typedef struct ogs_event_s {
     } sbi;
 
     struct {
-        const bson_t *document;
+        void *document;
     } dbi;
 } ogs_event_t;
 
diff --git a/src/hss/hss-sm.c b/src/hss/hss-sm.c
index 60ce6d4ea..c7e26be5f 100644
--- a/src/hss/hss-sm.c
+++ b/src/hss/hss-sm.c
@@ -90,7 +90,7 @@ void hss_state_operational(ogs_fsm_t *s, ogs_event_t *e)
         ogs_assert(e->dbi.document);
         hss_handle_change_event(e->dbi.document);
 
-        bson_destroy((bson_t*)e->dbi.document);
+        bson_destroy(e->dbi.document);
         break;
 
     default: