+# 2.6.32 has new BDI interface.
+AC_DEFUN([LC_NEW_BACKING_DEV_INFO],
+[AC_MSG_CHECKING([if backing_dev_info has a wb_cnt field])
+LB_LINUX_TRY_COMPILE([
+ #include <linux/backing-dev.h>
+],[
+ struct backing_dev_info bdi;
+ bdi.wb_cnt = 0;
+],[
+ AC_MSG_RESULT(yes)
+ AC_DEFINE(HAVE_NEW_BACKING_DEV_INFO, 1,
+ [backing_dev_info has a wb_cnt field])
+],[
+ AC_MSG_RESULT(no)
+])
+])
+
+# 2.6.24 has bdi_init()/bdi_destroy() functions.
+AC_DEFUN([LC_EXPORT_BDI_INIT],
+[LB_CHECK_SYMBOL_EXPORT([bdi_init],
+[mm/backing-dev.c],[
+ AC_DEFINE(HAVE_BDI_INIT, 1,
+ [bdi_init/bdi_destroy functions are present])
+],[
+])
+])
+