[PATCH] uml: tidying COW code

Improve (especially for coherence) some prototypes, and return code of
init_cow_file in error case - for a short write return -EINVAL, otherwise
return the error we got!

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 101efd2..fa617e0 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1135,7 +1135,7 @@
 static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
 {
 	unsigned long modtime;
-	long long actual;
+	unsigned long long actual;
 	int err;
 
 	err = os_file_modtime(file, &modtime);