From 3ea05b558ba577d5c1c574a8161bc0d089290ea5 Mon Sep 17 00:00:00 2001
From: markj <markj@FreeBSD.org>
Date: Thu, 19 Mar 2015 23:07:04 +0000
Subject: MFC r279896: Document m_collapse().

---
 share/man/man9/mbuf.9 | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

(limited to 'share/man/man9')

diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9
index 42fe372..fd2dddc 100644
--- a/share/man/man9/mbuf.9
+++ b/share/man/man9/mbuf.9
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 13, 2012
+.Dd March 11, 2015
 .Dt MBUF 9
 .Os
 .\"
@@ -136,6 +136,8 @@
 .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
@@ -974,6 +976,20 @@ depending on the caller's preference.
 This function is especially useful in network drivers, where
 certain long mbuf chains must be shortened before being added
 to TX descriptor lists.
+.It Fn m_collapse m0 how maxfrags
+Defragment an mbuf chain, returning a chain of at most
+.Fa maxfrags
+mbufs and clusters.
+If allocation fails or the chain cannot be collapsed as requested,
+.Dv NULL
+will be returned, with the original chain possibly modified.
+As with
+.Fn m_defrag ,
+.Fa how
+should be one of
+.Dv M_WAITOK
+or
+.Dv M_NOWAIT .
 .It Fn m_unshare m0 how
 Create a version of the specified mbuf chain whose
 contents can be safely modified without affecting other users.
-- 
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