Document new 'what' value for sx_assert(9).

PS. There is a inconsistency in this manual page, because in
    non-WITNESS case sx_assert(9) does not panics, it only prints
    the warning. I haven't fixed this, because jhb@ is planing to
    replace those printf()s with panic()s.

Reviewed by:	jhb
Approved by:	jhb, scottl (mentor)

1 files changed, 6 insertions, 1 deletions

diff --git a/share/man/man9/sx.9 b/share/man/man9/sx.9
index 12158e7..5dce1be 100644
--- a/share/man/man9/sx.9
+++ b/share/man/man9/sx.9
@@ -136,7 +136,7 @@ for the assertions specified in
 .Ar what
 and panics if they are not met.
 The following assertions are supported:
-.Bl -tag -width ".Dv SX_XLOCKED"
+.Bl -tag -width ".Dv SX_UNLOCKED"
 .It Dv SX_LOCKED
 Assert that the current thread has either a shared or an exclusive lock on the
 .Vt sx
@@ -151,6 +151,11 @@ Assert that the current thread has an exclusive lock on the
 .Vt sx
 lock pointed to
 by the first argument.
+.It Dv SX_UNLOCKED
+Assert that the current thread has no lock on the
+.Vt sx
+lock pointed to
+by the first argument.
 .El
 .Pp
 The