Document that devclass_get_maxunit(9) returns one greater than the current

highest unit.

Reviewed by:	dfr
MFC after:	2 weeks

share/man/man9/devclass_get_maxunit.9

@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 16, 1998
+.Dd April 3, 2005
 .Dt DEVCLASS_GET_MAXUNIT 9
 .Os
 .Sh NAME
@@ -40,12 +40,14 @@
 .Ft int
 .Fn devclass_get_maxunit "devclass_t dc"
 .Sh DESCRIPTION
-Returns the maximum unit number allocated to device instances in the
-specified
+Returns the next unit number to be allocated to device instances in the
 .Dv devclass .
+This is one greater than the highest currently allocated unit.
 .Sh SEE ALSO
 .Xr devclass 9 ,
 .Xr device 9
 .Sh AUTHORS
 This man page was written by
 .An Doug Rabson .
+.Sh BUGS
+The name is confusing since it is one greater than the maximum unit.

sys/kern/subr_bus.c

@@ -1194,6 +1194,9 @@ devclass_get_count(devclass_t dc)
 /**
  * @brief Get the maximum unit number used in a devclass
  *
+ * Note that this is one greater than the highest currently-allocated
+ * unit.
+ *
  * @param dc		the devclass to examine
  */
 int