treat external storage allocated by the mbuf layer the same as

external storage attached to an mbuf anywhere else. this means it
uses MEXTADD to wire it up to the mbuf, and it relies on the ext_free
and ext_arg bits in the header to call the right free function
against the right pool.

M_CLUSTER gets renamed to M_EXTWR. the type field in MEXTADD gets
reused as a flags field so anything attaching storage to an mbuf
can say if it is writable or not.

ok claudio@

1 files changed, 5 insertions, 4 deletions

diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9
index ae4cde5f5d8..52a1c98375c 100644
--- a/share/man/man9/mbuf.9
+++ b/share/man/man9/mbuf.9
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: mbuf.9,v 1.73 2014/07/13 05:23:24 dlg Exp $
+.\"     $OpenBSD: mbuf.9,v 1.74 2014/07/13 09:52:48 dlg Exp $
 .\"
 .\" Copyright (c) 2001 Jean-Jacques Bernard-Gundol <jjbg@openbsd.org>
 .\" All rights reserved.
@@ -83,7 +83,7 @@
 .Fn MCLGET "struct mbuf *m" "int how"
 .Ft struct mbuf *
 .Fn MCLGETI "struct mbuf *m" "int how" "struct ifnet *ifp" "int len"
-.Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int type" \
+.Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int flags" \
 "void (*free)(caddr_t, u_int, void *)" "void *arg"
 .Fn M_ALIGN "struct mbuf *m" "int len"
 .Fn MH_ALIGN "struct mbuf *m" "int len"
@@ -636,11 +636,12 @@ See
 .Fn m_get
 for a description of
 .Fa how .
-.It Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int type" \
+.It Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int flags" \
 "void (*free)(caddr_t, u_int, void *)" "void *arg"
 Add pre-allocated storage to the mbuf pointed to by
 .Fa m .
-On success, the flag M_EXT is set in the mbuf.
+On success, the flag M_EXT is set in the mbuf, and M_EXTWR if specified in
+.Fa flags ..
 .It Fn M_ALIGN "struct mbuf *m" "int len"
 Set the
 .Fa m_data