diff --git a/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_fs_tbl.c b/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_fs_tbl.c
index 94706779c20e..b88541f3a440 100644
--- a/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_fs_tbl.c
+++ b/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_fs_tbl.c
@@ -143,7 +143,7 @@ static const struct {
 	{ "hpfs",	&OIDX_hrFSHPFS_c },
 	{ "smbfs",	&OIDX_hrFSOther_c },
 };
-#define	N_FS_TYPE_MAP	(sizeof(fs_type_map) / sizeof(fs_type_map[0]))
+#define	N_FS_TYPE_MAP	nitems(fs_type_map)
 
 /**
  * Create an entry into the FS table and an entry in the map (if needed).