diff --git a/diff.h b/diff.h
index f51a8ee..3edb705 100644
--- a/diff.h
+++ b/diff.h
@@ -209,10 +209,7 @@
 			const char *fullpath,
 			unsigned dirty_submodule1, unsigned dirty_submodule2);
 
-extern struct diff_filepair *diff_unmerge(struct diff_options *,
-			 const char *path,
-			 unsigned mode,
-			 const unsigned char *sha1);
+extern struct diff_filepair *diff_unmerge(struct diff_options *, const char *path);
 
 #define DIFF_SETUP_REVERSE      	1
 #define DIFF_SETUP_USE_CACHE		2