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mpls: no longer hold RTNL in mpls_netconf_dump_devconf()

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- Use for_each_netdev_dump() to no longer rely
  on net->dev_index_head hash table.

- No longer care of net->dev_base_seq

- Fix return value at the end of a dump,
  so that NLMSG_DONE can be appended to current skb,
  saving one recvmsg() system call.

- No longer grab RTNL, RCU protection is enough,
  afer adding one READ_ONCE(mdev->input_enabled)
  in mpls_netconf_fill_devconf()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240410111951.2673193-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-04-10 11:19:50 +00:00 committed by Jakub Kicinski
parent e1eb10f8ef
commit e0f89d2864
1 changed files with 22 additions and 37 deletions
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59
net/mpls/af_mpls.c
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@ -1154,7 +1154,7 @@ static int mpls_netconf_fill_devconf(struct sk_buff *skb, struct mpls_dev *mdev,
if ((all || type == NETCONFA_INPUT) &&
nla_put_s32(skb, NETCONFA_INPUT,
mdev->input_enabled) < 0)
READ_ONCE(mdev->input_enabled)) < 0)
goto nla_put_failure;
nlmsg_end(skb, nlh);
@ -1303,11 +1303,12 @@ static int mpls_netconf_dump_devconf(struct sk_buff *skb,
{
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
struct hlist_head *head;
struct {
unsigned long ifindex;
} *ctx = (void *)cb->ctx;
struct net_device *dev;
struct mpls_dev *mdev;
int idx, s_idx;
int h, s_h;
int err = 0;
if (cb->strict_check) {
struct netlink_ext_ack *extack = cb->extack;
@ -1324,40 +1325,23 @@ static int mpls_netconf_dump_devconf(struct sk_buff *skb,
}
}
s_h = cb->args[0];
s_idx = idx = cb->args[1];
for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
idx = 0;
head = &net->dev_index_head[h];
rcu_read_lock();
cb->seq = net->dev_base_seq;
hlist_for_each_entry_rcu(dev, head, index_hlist) {
if (idx < s_idx)
goto cont;
mdev = mpls_dev_get(dev);
if (!mdev)
goto cont;
if (mpls_netconf_fill_devconf(skb, mdev,
NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq,
RTM_NEWNETCONF,
NLM_F_MULTI,
NETCONFA_ALL) < 0) {
rcu_read_unlock();
goto done;
}
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
idx++;
}
rcu_read_unlock();
rcu_read_lock();
for_each_netdev_dump(net, dev, ctx->ifindex) {
mdev = mpls_dev_get(dev);
if (!mdev)
continue;
err = mpls_netconf_fill_devconf(skb, mdev,
NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq,
RTM_NEWNETCONF,
NLM_F_MULTI,
NETCONFA_ALL);
if (err < 0)
break;
}
done:
cb->args[0] = h;
cb->args[1] = idx;
rcu_read_unlock();
return skb->len;
return err;
}
#define MPLS_PERDEV_SYSCTL_OFFSET(field) \
@ -2773,7 +2757,8 @@ static int __init mpls_init(void)
mpls_getroute, mpls_dump_routes, 0);
rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
mpls_netconf_get_devconf,
mpls_netconf_dump_devconf, 0);
mpls_netconf_dump_devconf,
RTNL_FLAG_DUMP_UNLOCKED);
err = ipgre_tunnel_encap_add_mpls_ops();
if (err)
pr_err("Can't add mpls over gre tunnel ops\n");