ipv6: anycast: Don't hold RTNL for IPV6_LEAVE_ANYCAST and IPV6_ADDRFORM.

inet6_sk(sk)->ipv6_ac_list is protected by lock_sock().

In ipv6_sock_ac_drop() and ipv6_sock_ac_close(),
only __dev_get_by_index() and __in6_dev_get() requrie RTNL.

Let's replace them with dev_get_by_index() and in6_dev_get()
and drop RTNL from IPV6_LEAVE_ANYCAST and IPV6_ADDRFORM.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250702230210.3115355-13-kuni1840@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index f510df93b1e9549c1fa160b6f8260eacdd7616de..8440e7b27f6d61a551a35d7f5b3bcf949c0abe64 100644 (file)
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -158,12 +158,10 @@ error:
  */
 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 {
-       struct ipv6_pinfo *np = inet6_sk(sk);
-       struct net_device *dev;
        struct ipv6_ac_socklist *pac, *prev_pac;
+       struct ipv6_pinfo *np = inet6_sk(sk);
        struct net *net = sock_net(sk);
-
-       ASSERT_RTNL();
+       struct net_device *dev;
 
        prev_pac = NULL;
        for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
@@ -179,9 +177,11 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
        else
                np->ipv6_ac_list = pac->acl_next;
 
-       dev = __dev_get_by_index(net, pac->acl_ifindex);
-       if (dev)
+       dev = dev_get_by_index(net, pac->acl_ifindex);
+       if (dev) {
                ipv6_dev_ac_dec(dev, &pac->acl_addr);
+               dev_put(dev);
+       }
 
        sock_kfree_s(sk, pac, sizeof(*pac));
        return 0;
@@ -190,21 +190,20 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 void __ipv6_sock_ac_close(struct sock *sk)
 {
        struct ipv6_pinfo *np = inet6_sk(sk);
+       struct net *net = sock_net(sk);
        struct net_device *dev = NULL;
        struct ipv6_ac_socklist *pac;
-       struct net *net = sock_net(sk);
-       int     prev_index;
+       int prev_index = 0;
 
-       ASSERT_RTNL();
        pac = np->ipv6_ac_list;
        np->ipv6_ac_list = NULL;
 
-       prev_index = 0;
        while (pac) {
                struct ipv6_ac_socklist *next = pac->acl_next;
 
                if (pac->acl_ifindex != prev_index) {
-                       dev = __dev_get_by_index(net, pac->acl_ifindex);
+                       dev_put(dev);
+                       dev = dev_get_by_index(net, pac->acl_ifindex);
                        prev_index = pac->acl_ifindex;
                }
                if (dev)
@@ -212,6 +211,8 @@ void __ipv6_sock_ac_close(struct sock *sk)
                sock_kfree_s(sk, pac, sizeof(*pac));
                pac = next;
        }
+
+       dev_put(dev);
 }
 
 void ipv6_sock_ac_close(struct sock *sk)
@@ -220,9 +221,8 @@ void ipv6_sock_ac_close(struct sock *sk)
 
        if (!np->ipv6_ac_list)
                return;
-       rtnl_lock();
+
        __ipv6_sock_ac_close(sk);
-       rtnl_unlock();
 }
 
 static void ipv6_add_acaddr_hash(struct net *net, struct ifacaddr6 *aca)
@@ -413,14 +413,18 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
        return 0;
 }
 
-/* called with rtnl_lock() */
 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr)
 {
-       struct inet6_dev *idev = __in6_dev_get(dev);
+       struct inet6_dev *idev = in6_dev_get(dev);
+       int err;
 
        if (!idev)
                return -ENODEV;
-       return __ipv6_dev_ac_dec(idev, addr);
+
+       err = __ipv6_dev_ac_dec(idev, addr);
+       in6_dev_put(idev);
+
+       return err;
 }
 
 void ipv6_ac_destroy_dev(struct inet6_dev *idev)

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 0c870713b08cefa0eddc03415a861363cbaeb398..3d891aa6e7f522b7e1d11a9846a38af7991ad336 100644 (file)
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -120,9 +120,7 @@ struct ipv6_txoptions *ipv6_update_options(struct sock *sk,
 static bool setsockopt_needs_rtnl(int optname)
 {
        switch (optname) {
-       case IPV6_ADDRFORM:
        case IPV6_JOIN_ANYCAST:
-       case IPV6_LEAVE_ANYCAST:
                return true;
        }
        return false;