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net: Do delayed neigh confirmation.

Browse source 
When a dst_confirm() happens, mark the confirmation as pending in the
dst.  Then on the next packet out, when we have the neigh in-hand, do
the update.

This removes the dependency in dst_confirm() of dst's having an
attached neigh.

While we're here, remove the explicit 'dst' NULL check, all except 2
or 3 call sites ensure it's not NULL.  So just fix those cases up.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2012-07-02 02:21:03 -07:00
parent 60d354ebeb
commit 5110effee8
6 changed files with 38 additions and 32 deletions
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29
include/net/dst.h
View file

@ -51,7 +51,7 @@ struct dst_entry {
int (*input)(struct sk_buff *);
int (*output)(struct sk_buff *);
int flags;
unsigned short flags;
#define DST_HOST 0x0001
#define DST_NOXFRM 0x0002
#define DST_NOPOLICY 0x0004
@ -62,6 +62,8 @@ struct dst_entry {
#define DST_FAKE_RTABLE 0x0080
#define DST_XFRM_TUNNEL 0x0100
unsigned short pending_confirm;
short error;
short obsolete;
unsigned short header_len; /* more space at head required */
@ -371,7 +373,8 @@ static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
extern int dst_discard(struct sk_buff *skb);
extern void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
int initial_ref, int initial_obsolete, int flags);
int initial_ref, int initial_obsolete,
unsigned short flags);
extern void __dst_free(struct dst_entry *dst);
extern struct dst_entry *dst_destroy(struct dst_entry *dst);
@ -395,14 +398,24 @@ static inline void dst_rcu_free(struct rcu_head *head)
static inline void dst_confirm(struct dst_entry *dst)
{
if (dst) {
struct neighbour *n;
dst->pending_confirm = 1;
}
rcu_read_lock();
n = dst_get_neighbour_noref(dst);
neigh_confirm(n);
rcu_read_unlock();
static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
struct sk_buff *skb)
{
struct hh_cache *hh;
if (unlikely(dst->pending_confirm)) {
n->confirmed = jiffies;
dst->pending_confirm = 0;
}
hh = &n->hh;
if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
return neigh_hh_output(hh, skb);
else
return n->output(n, skb);
}
static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)

15
include/net/neighbour.h
View file

@ -309,12 +309,6 @@ static inline struct neighbour * neigh_clone(struct neighbour *neigh)
#define neigh_hold(n) atomic_inc(&(n)->refcnt)
static inline void neigh_confirm(struct neighbour *neigh)
{
if (neigh)
neigh->confirmed = jiffies;
}
static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
{
unsigned long now = jiffies;
@ -358,15 +352,6 @@ static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
return dev_queue_xmit(skb);
}
static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)
{
struct hh_cache *hh = &n->hh;
if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
return neigh_hh_output(hh, skb);
else
return n->output(n, skb);
}
static inline struct neighbour *
__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
{

3
net/core/dst.c
View file

@ -152,7 +152,7 @@ EXPORT_SYMBOL(dst_discard);
const u32 dst_default_metrics[RTAX_MAX];
void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
int initial_ref, int initial_obsolete, int flags)
int initial_ref, int initial_obsolete, unsigned short flags)
{
struct dst_entry *dst;
@ -188,6 +188,7 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
dst->__use = 0;
dst->lastuse = jiffies;
dst->flags = flags;
dst->pending_confirm = 0;
dst->next = NULL;
if (!(flags & DST_NOCOUNT))
dst_entries_add(ops, 1);

2
net/ipv4/ip_output.c
View file

@ -198,7 +198,7 @@ static inline int ip_finish_output2(struct sk_buff *skb)
if (unlikely(!neigh))
neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
if (neigh) {
int res = neigh_output(neigh, skb);
int res = dst_neigh_output(dst, neigh, skb);
rcu_read_unlock_bh();
return res;

19
net/ipv4/tcp_input.c
View file

@ -740,13 +740,13 @@ void tcp_update_metrics(struct sock *sk)
if (sysctl_tcp_nometrics_save)
return;
dst_confirm(dst);
if (dst && (dst->flags & DST_HOST)) {
const struct inet_connection_sock *icsk = inet_csk(sk);
int m;
unsigned long rtt;
dst_confirm(dst);
if (icsk->icsk_backoff || !tp->srtt) {
/* This session failed to estimate rtt. Why?
* Probably, no packets returned in time.
@ -3869,9 +3869,11 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
tcp_cong_avoid(sk, ack, prior_in_flight);
}
if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP))
dst_confirm(__sk_dst_get(sk));
if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) {
struct dst_entry *dst = __sk_dst_get(sk);
if (dst)
dst_confirm(dst);
}
return 1;
no_queue:
@ -6140,9 +6142,14 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
case TCP_FIN_WAIT1:
if (tp->snd_una == tp->write_seq) {
struct dst_entry *dst;
tcp_set_state(sk, TCP_FIN_WAIT2);
sk->sk_shutdown |= SEND_SHUTDOWN;
dst_confirm(__sk_dst_get(sk));
dst = __sk_dst_get(sk);
if (dst)
dst_confirm(dst);
if (!sock_flag(sk, SOCK_DEAD))
/* Wake up lingering close() */

2
net/ipv6/ip6_output.c
View file

@ -125,7 +125,7 @@ static int ip6_finish_output2(struct sk_buff *skb)
rcu_read_lock();
neigh = dst_get_neighbour_noref(dst);
if (neigh) {
int res = neigh_output(neigh, skb);
int res = dst_neigh_output(dst, neigh, skb);
rcu_read_unlock();
return res;