net: Modify sk_alloc to not reference count the netns of kernel sockets.

Now that sk_alloc knows when a kernel socket is being allocated modify
it to not reference count the network namespace of kernel sockets.

Keep track of if a socket needs reference counting by adding a flag to
struct sock called sk_net_refcnt.

Update all of the callers of sock_create_kern to stop using
sk_change_net and sk_release_kernel as those hacks are no longer
needed, to avoid reference counting a kernel socket.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 9 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index ae513a2fe7f3..f6b090df3930 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1334,9 +1334,10 @@ static void l2tp_tunnel_del_work(struct work_struct *work)
                 if (sock)
                         inet_shutdown(sock, 2);
         } else {
-                if (sock)
+                if (sock) {
                         kernel_sock_shutdown(sock, SHUT_RDWR);
-                sk_release_kernel(sk);
+                        sock_release(sock);
+                }
         }
 
         l2tp_tunnel_sock_put(sk);
@@ -1399,13 +1400,11 @@ static int l2tp_tunnel_sock_create(struct net *net,
                 if (cfg->local_ip6 && cfg->peer_ip6) {
                         struct sockaddr_l2tpip6 ip6_addr = {0};
 
-                        err = sock_create_kern(&init_net, AF_INET6, SOCK_DGRAM,
+                        err = sock_create_kern(net, AF_INET6, SOCK_DGRAM,
                                           IPPROTO_L2TP, &sock);
                         if (err < 0)
                                 goto out;
 
-                        sk_change_net(sock->sk, net);
-
                         ip6_addr.l2tp_family = AF_INET6;
                         memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
                                sizeof(ip6_addr.l2tp_addr));
@@ -1429,13 +1428,11 @@ static int l2tp_tunnel_sock_create(struct net *net,
                 {
                         struct sockaddr_l2tpip ip_addr = {0};
 
-                        err = sock_create_kern(&init_net, AF_INET, SOCK_DGRAM,
+                        err = sock_create_kern(net, AF_INET, SOCK_DGRAM,
                                           IPPROTO_L2TP, &sock);
                         if (err < 0)
                                 goto out;
 
-                        sk_change_net(sock->sk, net);
-
                         ip_addr.l2tp_family = AF_INET;
                         ip_addr.l2tp_addr = cfg->local_ip;
                         ip_addr.l2tp_conn_id = tunnel_id;
@@ -1462,7 +1459,7 @@ out:
         *sockp = sock;
         if ((err < 0) && sock) {
                 kernel_sock_shutdown(sock, SHUT_RDWR);
-                sk_release_kernel(sock->sk);
+                sock_release(sock);
                 *sockp = NULL;
         }