XXXX give me a better summary

@@ -206,10 +206,11 @@
 #define SA_NOT  0x01    /* Must have slot from swap dev other than input one */
 
 /* Special error codes for swap_newphysname() */
 #define SE_NOSWAP       -1      /* No physical swap slots available */
 #define SE_NOANON       -2      /* No anon slot for swap slot */
+#define SE_NODEV        -3      /* No swap devices on this machine. */
 
 #ifdef _KERNEL
 extern struct anon *swap_anon(struct vnode *vp, u_offset_t off);
 extern int swap_phys_alloc(struct vnode **vpp, u_offset_t *offp, size_t *lenp,
     uint_t flags);