diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index a5538433c927..91a063a1f3b3 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -630,7 +630,7 @@ do {									\
  */
 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
 
-static inline sector_t to_sector(unsigned long n)
+static inline sector_t to_sector(unsigned long long n)
 {
 	return (n >> SECTOR_SHIFT);
 }