diff --git a/fs/isofs/zisofs.h b/fs/isofs/zisofs.h
index d78485d..2737957 100644
--- a/fs/isofs/zisofs.h
+++ b/fs/isofs/zisofs.h
@@ -15,7 +15,7 @@
  */
 
 #ifdef CONFIG_ZISOFS
-extern struct address_space_operations zisofs_aops;
+extern const struct address_space_operations zisofs_aops;
 extern int __init zisofs_init(void);
 extern void zisofs_cleanup(void);
 #endif