mbuf.9 patch rev 2

Index: mbuf.9
===================================================================
--- mbuf.9	(revision 260701)
+++ mbuf.9	(working copy)
@@ -72,8 +72,10 @@
 .Ft struct mbuf *
 .Fn m_get "int how" "int type"
 .Ft struct mbuf *
-.Fn m_getm "struct mbuf *orig" "int len" "int how" "int type"
+.Fn m_getm "struct mbuf *m" "int len" "int how" "short type"
 .Ft struct mbuf *
+.Fn m_getm2 "struct mbuf *m" "int len" "int how" "short type" "int flags"
+.Ft struct mbuf *
 .Fn m_getcl "int how" "short type" "int flags"
 .Ft struct mbuf *
 .Fn m_getclr "int how" "int type"
@@ -136,6 +138,8 @@
 .Ft struct mbuf *
 .Fn m_defrag "struct mbuf *m0" "int how"
 .Ft struct mbuf *
+.Fn m_collapse "struct mbuf *m0" "int how" "int maxfrags"
+.Ft struct mbuf *
 .Fn m_unshare "struct mbuf *m0" "int how"
 .\"
 .Sh DESCRIPTION
@@ -538,7 +542,15 @@
 A function version of
 .Fn MGET
 for non-critical paths.
-.It Fn m_getm orig len how type
+.It Fn m_getm m len how type
+A wrapper macro for
+.Fn m_getm2
+specifying
+.Dv M_PKTHDR
+as the
+.Fa flags
+parameter.
+.It Fn m_getm2 m len how type flags
 Allocate
 .Fa len
 bytes worth of
@@ -549,7 +561,7 @@
 .Vt mbuf chain
 to the
 .Vt mbuf chain
-.Fa orig ,
+.Fa m ,
 if it is
 .No non- Ns Dv NULL .
 If the allocation fails at any point,
@@ -556,12 +568,12 @@
 free whatever was allocated and return
 .Dv NULL .
 If
-.Fa orig
+.Fa m
 is
 .No non- Ns Dv NULL ,
 it will not be freed.
 It is possible to use
-.Fn m_getm
+.Fn m_getm2
 to either append
 .Fa len
 bytes to an existing
@@ -573,7 +585,19 @@
 .Vt mbuf
 and
 .Vt mbuf cluster
-allocation.
+allocation. Valid
+.Fa flags
+are
+.Dv M_PKTHDR
+and
+.Dv M_EOR
+but if
+.Fa m
+is
+.No non- Ns Dv NULL
+then
+.Dv M_PKTHDR
+will be ignored.
 .It Fn m_gethdr how type
 A function version of
 .Fn MGETHDR
@@ -973,8 +997,19 @@
 depending on the caller's preference.
 .Pp
 This function is especially useful in network drivers, where
-certain long mbuf chains must be shortened before being added
-to TX descriptor lists.
+certain long
+.Vt mbuf chains
+must be shortened before being added to TX descriptor lists.
+.It Fn m_collapse m0 how maxfrags
+Collapse an mbuf chain, returning at most
+.Fa maxfrags
+separate
+.Vt mbufs+clusters .
+If this is not possible
+.Dv NULL
+is returned and the original
+.Vt mbuf chain
+is left in its present (potentially modified) state.
 .It Fn m_unshare m0 how
 Create a version of the specified mbuf chain whose
 contents can be safely modified without affecting other users.