From 46f5182dd792c55940ca520576d1544744732b81 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 6 Mar 2024 15:51:42 +0000
Subject: [PATCH] ipv6: make in6_dump_addrs() lockless
in6_dump_addrs() is called with RCU protection.
There is no need holding idev->lock to iterate through unicast addresses.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/addrconf.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 5864a1fc6850a..c662972d92063 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5271,23 +5271,22 @@ static int inet6_fill_ifacaddr(struct sk_buff *skb,
}
/* called with rcu_read_lock() */
-static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
+static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
struct netlink_callback *cb, int s_ip_idx,
struct inet6_fill_args *fillargs)
{
- struct ifmcaddr6 *ifmca;
- struct ifacaddr6 *ifaca;
+ const struct ifmcaddr6 *ifmca;
+ const struct ifacaddr6 *ifaca;
int ip_idx = 0;
int err = 1;
- read_lock_bh(&idev->lock);
switch (fillargs->type) {
case UNICAST_ADDR: {
- struct inet6_ifaddr *ifa;
+ const struct inet6_ifaddr *ifa;
fillargs->event = RTM_NEWADDR;
/* unicast address incl. temp addr */
- list_for_each_entry(ifa, &idev->addr_list, if_list) {
+ list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
if (ip_idx < s_ip_idx)
goto next;
err = inet6_fill_ifaddr(skb, ifa, fillargs);
@@ -5300,7 +5299,6 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
break;
}
case MULTICAST_ADDR:
- read_unlock_bh(&idev->lock);
fillargs->event = RTM_GETMULTICAST;
/* multicast address */
@@ -5313,7 +5311,6 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
if (err < 0)
break;
}
- read_lock_bh(&idev->lock);
break;
case ANYCAST_ADDR:
fillargs->event = RTM_GETANYCAST;
@@ -5330,7 +5327,6 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
default:
break;
}
- read_unlock_bh(&idev->lock);
cb->args[2] = ip_idx;
return err;
}
--
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