diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index 40b502e..bdf3860 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -42,7 +42,7 @@
 			 const void *src2, size_t src2_len);
 
 /* armor.c */
-extern int ceph_armor(char *dst, const void *src, const void *end);
-extern int ceph_unarmor(void *dst, const char *src, const char *end);
+extern int ceph_armor(char *dst, const char *src, const char *end);
+extern int ceph_unarmor(char *dst, const char *src, const char *end);
 
 #endif