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- Simplify handling of the deferring of mbuf transmit until after lle lock drop

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- add a couple of comments to clarify intent
This commit is contained in:
Kip Macy 2008-12-16 23:06:36 +00:00
parent 09efca80df
commit fd14c50bbb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=186196
1 changed files with 28 additions and 12 deletions
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40
sys/netinet6/nd6.c
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@ -1407,7 +1407,7 @@ nd6_cache_lladdr(struct ifnet *ifp, struct in6_addr *from, char *lladdr,
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, struct in6_addr *from, char *lladdr,
* 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 ifnet *origifp, struct mbuf *m0,
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 ifnet *origifp, struct mbuf *m0,
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 ifnet *origifp, struct mbuf *m0,
#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);
}