diff --git a/src/database/sql/convert.go b/src/database/sql/convert.go
index 2149a8e700..7a3b5fa7da 100644
--- a/src/database/sql/convert.go
+++ b/src/database/sql/convert.go
@@ -98,10 +98,12 @@ func defaultCheckNamedValue(nv *driver.NamedValue) (err error) {
 	return err
 }
 
-// driverArgs converts arguments from callers of Stmt.Exec and
+// driverArgsConnLocked converts arguments from callers of Stmt.Exec and
 // Stmt.Query into driver Values.
 //
 // The statement ds may be nil, if no statement is available.
+//
+// ci must be locked.
 func driverArgsConnLocked(ci driver.Conn, ds *driverStmt, args []interface{}) ([]driver.NamedValue, error) {
 	nvargs := make([]driver.NamedValue, len(args))