Implement MBUF_STRESS_TEST mark II.

Changes from the original implementation:

- Fragmentation is handled by the function m_fragment, which can
be called from whereever fragmentation is needed.  Note that this
function is wrapped in #ifdef MBUF_STRESS_TEST to discourage non-testing
use.

- m_fragment works slightly differently from the old fragmentation
code in that it allocates a seperate mbuf cluster for each fragment.
This defeats dma_map_load_mbuf/buffer's feature of coalescing adjacent
fragments.  While that is a nice feature in practice, it nerfed the
usefulness of mbuf_stress_test.

- Add two modes of random fragmentation.  Chains with fragments all of
the same random length and chains with fragments that are each uniquely
random in length may now be requested.

1 files changed, 2 insertions, 18 deletions

diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 4a507cf..f6a70ef 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -1030,24 +1030,8 @@ pass:
 #endif
 
 #ifdef MBUF_STRESS_TEST
-		if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
-			struct mbuf *m1, *m2;
-			int length, tmp;
-
-			tmp = length = m->m_pkthdr.len;
-
-			while ((length -= mbuf_frag_size) >= 1) {
-				m1 = m_split(m, length, M_DONTWAIT);
-				if (m1 == NULL)
-					break;
-				m1->m_flags &= ~M_PKTHDR;
-				m2 = m;
-				while (m2->m_next != NULL)
-					m2 = m2->m_next;
-				m2->m_next = m1;
-				m->m_pkthdr.len = tmp;
-			}
-		}
+		if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
+			m = m_fragment(m, M_DONTWAIT, mbuf_frag_size);
 #endif
 		error = (*ifp->if_output)(ifp, m,
 				(struct sockaddr *)dst, ro->ro_rt);