svn commit: r186196 - head/sys/netinet6
Kip Macy
kmacy at FreeBSD.org
Tue Dec 16 23:06:38 UTC 2008
Author: kmacy
Date: Tue Dec 16 23:06:36 2008
New Revision: 186196
URL: http://svn.freebsd.org/changeset/base/186196
Log:
- Simplify handling of the deferring of mbuf transmit until after lle lock drop
- add a couple of comments to clarify intent
Modified:
head/sys/netinet6/nd6.c
Modified: head/sys/netinet6/nd6.c
==============================================================================
--- head/sys/netinet6/nd6.c Tue Dec 16 22:16:34 2008 (r186195)
+++ head/sys/netinet6/nd6.c Tue Dec 16 23:06:36 2008 (r186196)
@@ -1407,7 +1407,7 @@ nd6_cache_lladdr(struct ifnet *ifp, stru
int newstate = 0;
uint16_t router = 0;
struct sockaddr_in6 sin6;
- struct mbuf *tail = NULL, *chain = NULL;
+ struct mbuf *chain = NULL;
int static_route = 0;
IF_AFDATA_UNLOCK_ASSERT(ifp);
@@ -1526,11 +1526,14 @@ nd6_cache_lladdr(struct ifnet *ifp, stru
* just set the 2nd argument as the
* 1st one.
*/
- nd6_output_lle(ifp, ifp, m_hold, L3_ADDR_SIN6(ln), NULL, ln, &tail);
- if ((tail != NULL) && chain == (NULL))
- chain = tail;
+ nd6_output_lle(ifp, ifp, m_hold, L3_ADDR_SIN6(ln), NULL, ln, &chain);
}
- if (chain)
+ /*
+ * If we have mbufs in the chain we need to do
+ * deferred transmit. Copy the address from the
+ * llentry before dropping the lock down below.
+ */
+ if (chain != NULL)
memcpy(&sin6, L3_ADDR_SIN6(ln), sizeof(sin6));
}
} else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
@@ -1706,7 +1709,7 @@ nd6_output(struct ifnet *ifp, struct ifn
int
nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
struct sockaddr_in6 *dst, struct rtentry *rt0, struct llentry *lle,
- struct mbuf **tail)
+ struct mbuf **chain)
{
INIT_VNET_INET6(curvnet);
struct mbuf *m = m0;
@@ -1720,7 +1723,7 @@ nd6_output_lle(struct ifnet *ifp, struct
LLE_WLOCK_ASSERT(lle);
- KASSERT(tail != NULL, (" lle locked but no tail pointer passed"));
+ KASSERT(chain != NULL, (" lle locked but no mbuf chain pointer passed"));
}
#endif
if (IN6_IS_ADDR_MULTICAST(&dst->sin6_addr))
@@ -1888,12 +1891,25 @@ nd6_output_lle(struct ifnet *ifp, struct
#ifdef MAC
mac_netinet6_nd6_send(ifp, m);
#endif
+ /*
+ * We were passed in a pointer to an lle with the lock held
+ * this means that we can't call if_output as we will
+ * recurse on the lle lock - so what we do is we create
+ * a list of mbufs to send and transmit them in the caller
+ * after the lock is dropped
+ */
if (lle != NULL) {
- if (*tail == NULL)
- *tail = m;
- else {
- (*tail)->m_nextpkt = m;
- *tail = m;
+ if (*chain == NULL)
+ *chain = m;
+ else {
+ struct mbuf *m = *chain;
+
+ /*
+ * append mbuf to end of deferred chain
+ */
+ while (m->m_nextpkt != NULL)
+ m = m->m_nextpkt;
+ m->m_nextpkt = m;
}
return (error);
}
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