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Message-ID: <20240403123913.4173904-1-edumazet@google.com>
Date: Wed, 3 Apr 2024 12:39:13 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, David Ahern <dsahern@...nel.org>
Cc: netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next] ipv6: remove RTNL protection from ip6addrlbl_dump()
No longer hold RTNL while calling ip6addrlbl_dump()
("ip addrlabel show")
ip6addrlbl_dump() was already mostly relying on RCU anyway.
Add READ_ONCE()/WRITE_ONCE() annotations around
net->ipv6.ip6addrlbl_table.seq
Also change return value for a completed dump,
so that NLMSG_DONE can be appended to current skb,
saving one recvmsg() system call.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv6/addrlabel.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index 17ac45aa7194ce9c148ed95e14dd575d17feeb98..961e853543b64cd2060ef693ae3ad32a44780aa1 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -234,7 +234,8 @@ static int __ip6addrlbl_add(struct net *net, struct ip6addrlbl_entry *newp,
hlist_add_head_rcu(&newp->list, &net->ipv6.ip6addrlbl_table.head);
out:
if (!ret)
- net->ipv6.ip6addrlbl_table.seq++;
+ WRITE_ONCE(net->ipv6.ip6addrlbl_table.seq,
+ net->ipv6.ip6addrlbl_table.seq + 1);
return ret;
}
@@ -445,7 +446,7 @@ static void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
};
static int ip6addrlbl_fill(struct sk_buff *skb,
- struct ip6addrlbl_entry *p,
+ const struct ip6addrlbl_entry *p,
u32 lseq,
u32 portid, u32 seq, int event,
unsigned int flags)
@@ -498,7 +499,7 @@ static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
struct net *net = sock_net(skb->sk);
struct ip6addrlbl_entry *p;
int idx = 0, s_idx = cb->args[0];
- int err;
+ int err = 0;
if (cb->strict_check) {
err = ip6addrlbl_valid_dump_req(nlh, cb->extack);
@@ -510,7 +511,7 @@ static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
if (idx >= s_idx) {
err = ip6addrlbl_fill(skb, p,
- net->ipv6.ip6addrlbl_table.seq,
+ READ_ONCE(net->ipv6.ip6addrlbl_table.seq),
NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq,
RTM_NEWADDRLABEL,
@@ -522,7 +523,7 @@ static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
}
rcu_read_unlock();
cb->args[0] = idx;
- return skb->len;
+ return err;
}
static inline int ip6addrlbl_msgsize(void)
@@ -614,7 +615,7 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
rcu_read_lock();
p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
- lseq = net->ipv6.ip6addrlbl_table.seq;
+ lseq = READ_ONCE(net->ipv6.ip6addrlbl_table.seq);
if (p)
err = ip6addrlbl_fill(skb, p, lseq,
NETLINK_CB(in_skb).portid,
@@ -647,6 +648,7 @@ int __init ipv6_addr_label_rtnl_register(void)
return ret;
ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETADDRLABEL,
ip6addrlbl_get,
- ip6addrlbl_dump, RTNL_FLAG_DOIT_UNLOCKED);
+ ip6addrlbl_dump, RTNL_FLAG_DOIT_UNLOCKED |
+ RTNL_FLAG_DUMP_UNLOCKED);
return ret;
}
--
2.44.0.478.gd926399ef9-goog
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