From 9cc4cc329d30dbb353fbb23ef8cd633e8f5b8ccf Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 6 Mar 2024 15:51:43 +0000
Subject: [PATCH] ipv6: use xa_array iterator to implement inet6_dump_addr()
inet6_dump_addr() can use the new xa_array iterator
for better scalability.
Make it ready for RCU-only protection.
RTNL use is removed in the following patch.
Also properly return 0 at the end of a dump to avoid
and extra recvmsg() to get NLMSG_DONE.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/addrconf.c | 79 +++++++++++++++++----------------------------
1 file changed, 30 insertions(+), 49 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c662972d92063..4359e49102490 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -717,7 +717,7 @@ static int inet6_netconf_get_devconf(struct sk_buff *in_skb,
static u32 inet6_base_seq(const struct net *net)
{
u32 res = atomic_read(&net->ipv6.dev_addr_genid) +
- net->dev_base_seq;
+ READ_ONCE(net->dev_base_seq);
/* Must not return 0 (see nl_dump_check_consistent()).
* Chose a value far away from 0.
@@ -5272,13 +5272,13 @@ static int inet6_fill_ifacaddr(struct sk_buff *skb,
/* called with rcu_read_lock() */
static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
- struct netlink_callback *cb, int s_ip_idx,
+ struct netlink_callback *cb, int *s_ip_idx,
struct inet6_fill_args *fillargs)
{
const struct ifmcaddr6 *ifmca;
const struct ifacaddr6 *ifaca;
int ip_idx = 0;
- int err = 1;
+ int err = 0;
switch (fillargs->type) {
case UNICAST_ADDR: {
@@ -5287,7 +5287,7 @@ static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
/* unicast address incl. temp addr */
list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
- if (ip_idx < s_ip_idx)
+ if (ip_idx < *s_ip_idx)
goto next;
err = inet6_fill_ifaddr(skb, ifa, fillargs);
if (err < 0)
@@ -5305,7 +5305,7 @@ static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
for (ifmca = rcu_dereference(idev->mc_list);
ifmca;
ifmca = rcu_dereference(ifmca->next), ip_idx++) {
- if (ip_idx < s_ip_idx)
+ if (ip_idx < *s_ip_idx)
continue;
err = inet6_fill_ifmcaddr(skb, ifmca, fillargs);
if (err < 0)
@@ -5317,7 +5317,7 @@ static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
/* anycast address */
for (ifaca = rcu_dereference(idev->ac_list); ifaca;
ifaca = rcu_dereference(ifaca->aca_next), ip_idx++) {
- if (ip_idx < s_ip_idx)
+ if (ip_idx < *s_ip_idx)
continue;
err = inet6_fill_ifacaddr(skb, ifaca, fillargs);
if (err < 0)
@@ -5327,7 +5327,7 @@ static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
default:
break;
}
- cb->args[2] = ip_idx;
+ *s_ip_idx = err ? ip_idx : 0;
return err;
}
@@ -5390,6 +5390,7 @@ static int inet6_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
enum addr_type_t type)
{
+ struct net *tgt_net = sock_net(skb->sk);
const struct nlmsghdr *nlh = cb->nlh;
struct inet6_fill_args fillargs = {
.portid = NETLINK_CB(cb->skb).portid,
@@ -5398,72 +5399,52 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
.netnsid = -1,
.type = type,
};
- struct net *tgt_net = sock_net(skb->sk);
- int idx, s_idx, s_ip_idx;
- int h, s_h;
+ struct {
+ unsigned long ifindex;
+ int ip_idx;
+ } *ctx = (void *)cb->ctx;
struct net_device *dev;
struct inet6_dev *idev;
- struct hlist_head *head;
int err = 0;
- s_h = cb->args[0];
- s_idx = idx = cb->args[1];
- s_ip_idx = cb->args[2];
-
rcu_read_lock();
if (cb->strict_check) {
err = inet6_valid_dump_ifaddr_req(nlh, &fillargs, &tgt_net,
skb->sk, cb);
if (err < 0)
- goto put_tgt_net;
+ goto done;
err = 0;
if (fillargs.ifindex) {
- dev = __dev_get_by_index(tgt_net, fillargs.ifindex);
- if (!dev) {
- err = -ENODEV;
- goto put_tgt_net;
- }
+ err = -ENODEV;
+ dev = dev_get_by_index_rcu(tgt_net, fillargs.ifindex);
+ if (!dev)
+ goto done;
idev = __in6_dev_get(dev);
- if (idev) {
- err = in6_dump_addrs(idev, skb, cb, s_ip_idx,
+ if (idev)
+ err = in6_dump_addrs(idev, skb, cb,
+ &ctx->ip_idx,
&fillargs);
- if (err > 0)
- err = 0;
- }
- goto put_tgt_net;
+ goto done;
}
}
cb->seq = inet6_base_seq(tgt_net);
- for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
- idx = 0;
- head = &tgt_net->dev_index_head[h];
- hlist_for_each_entry_rcu(dev, head, index_hlist) {
- if (idx < s_idx)
- goto cont;
- if (h > s_h || idx > s_idx)
- s_ip_idx = 0;
- idev = __in6_dev_get(dev);
- if (!idev)
- goto cont;
-
- if (in6_dump_addrs(idev, skb, cb, s_ip_idx,
- &fillargs) < 0)
- goto done;
-cont:
- idx++;
- }
+ for_each_netdev_dump(tgt_net, dev, ctx->ifindex) {
+ idev = __in6_dev_get(dev);
+ if (!idev)
+ continue;
+ err = in6_dump_addrs(idev, skb, cb, &ctx->ip_idx,
+ &fillargs);
+ if (err < 0)
+ goto done;
}
done:
- cb->args[0] = h;
- cb->args[1] = idx;
-put_tgt_net:
rcu_read_unlock();
if (fillargs.netnsid >= 0)
put_net(tgt_net);
- return skb->len ? : err;
+ return err;
}
static int inet6_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
--
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