])
])
+# 2.6.27 and some older have mapping->tree_lock as spin_lock
+AC_DEFUN([LC_RW_TREE_LOCK],
+[AC_MSG_CHECKING([mapping->tree_lock is rw_lock])
+tmp_flags="$EXTRA_KCFLAGS"
+EXTRA_KCFLAGS="-Werror"
+LB_LINUX_TRY_COMPILE([
+ #include <linux/fs.h>
+],[
+ struct address_space *map = NULL;
+
+ write_lock_irq(&map->tree_lock);
+],[
+ AC_MSG_RESULT(yes)
+ AC_DEFINE(HAVE_RW_TREE_LOCK, 1,
+ [mapping->tree_lock is rw_lock])
+],[
+ AC_MSG_RESULT(no)
+])
+EXTRA_KCFLAGS="$tmp_flags"
+])
+
#
# LC_PROG_LINUX
#
LC_INODE_PERMISION_2ARGS
LC_FILE_REMOVE_SUID
LC_TRYLOCKPAGE
+ LC_RW_TREE_LOCK
])
#