diff --git a/mm/mremap.c b/mm/mremap.c
index c5590afe71650a..f554320281ccd8 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -358,7 +358,9 @@ static unsigned long get_extent(enum pgt_entry entry, unsigned long old_addr,
 
 	next = (old_addr + size) & mask;
 	/* even if next overflowed, extent below will be ok */
-	extent = (next > old_end) ? old_end - old_addr : next - old_addr;
+	extent = next - old_addr;
+	if (extent > old_end - old_addr)
+		extent = old_end - old_addr;
 	next = (new_addr + size) & mask;
 	if (extent > next - new_addr)
 		extent = next - new_addr;