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fib: rules: no longer hold RTNL in fib_nl_dumprule()

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- fib rules are already RCU protected, RTNL is not needed
  to get them.

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

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240411133340.1332796-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-04-11 13:33:40 +00:00 committed by Jakub Kicinski
parent 195b7fc53c
commit 32affa5578
1 changed files with 9 additions and 8 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

17
net/core/fib_rules.c
View file

@ -1142,10 +1142,10 @@ static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
const struct nlmsghdr *nlh = cb->nlh; const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk); struct net *net = sock_net(skb->sk);
struct fib_rules_ops *ops; struct fib_rules_ops *ops;
int idx = 0, family; int err, idx = 0, family;
if (cb->strict_check) { if (cb->strict_check) {
int err = fib_valid_dumprule_req(nlh, cb->extack); err = fib_valid_dumprule_req(nlh, cb->extack);
if (err < 0) if (err < 0)
return err; return err;
@ -1158,17 +1158,17 @@ static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
if (ops == NULL) if (ops == NULL)
return -EAFNOSUPPORT; return -EAFNOSUPPORT;
dump_rules(skb, cb, ops); return dump_rules(skb, cb, ops);
return skb->len;
} }
err = 0;
rcu_read_lock(); rcu_read_lock();
list_for_each_entry_rcu(ops, &net->rules_ops, list) { list_for_each_entry_rcu(ops, &net->rules_ops, list) {
if (idx < cb->args[0] || !try_module_get(ops->owner)) if (idx < cb->args[0] || !try_module_get(ops->owner))
goto skip; goto skip;
if (dump_rules(skb, cb, ops) < 0) err = dump_rules(skb, cb, ops);
if (err < 0)
break; break;
cb->args[1] = 0; cb->args[1] = 0;
@ -1178,7 +1178,7 @@ static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
rcu_read_unlock(); rcu_read_unlock();
cb->args[0] = idx; cb->args[0] = idx;
return skb->len; return err;
} }
static void notify_rule_change(int event, struct fib_rule *rule, static void notify_rule_change(int event, struct fib_rule *rule,
@ -1293,7 +1293,8 @@ static int __init fib_rules_init(void)
int err; int err;
rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0); rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0); rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0); rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule,
RTNL_FLAG_DUMP_UNLOCKED);
err = register_pernet_subsys(&fib_rules_net_ops); err = register_pernet_subsys(&fib_rules_net_ops);
if (err < 0) if (err < 0)