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MFC r279896:

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Document m_collapse().
This commit is contained in:
markj 2015-03-19 23:07:04 +00:00
parent fc2b8b3929
commit 3ea05b558b
1 changed files with 17 additions and 1 deletions
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18
share/man/man9/mbuf.9
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@ -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.