add m_align, a function to align any type of mbuf (i.e. it

is a superset of M_ALIGN and MH_ALIGN)

Reviewed by:	several

1 files changed, 19 insertions, 0 deletions

diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index ce00553..6a0e9ba 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1382,3 +1382,22 @@ nospace:
 		m_freem(m_final);
 	return (NULL);
 }
+
+/*
+ * Set the m_data pointer of a newly-allocated mbuf
+ * to place an object of the specified size at the
+ * end of the mbuf, longword aligned.
+ */
+void
+m_align(struct mbuf *m, int len)
+{
+	int adjust;
+
+	if (m->m_flags & M_EXT)
+		adjust = m->m_ext.ext_size - len;
+	else if (m->m_flags & M_PKTHDR)
+		adjust = MHLEN - len;
+	else
+		adjust = MLEN - len;
+	m->m_data += adjust &~ (sizeof(long)-1);
+}