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>

diff --git a/include/net/inet_common.h b/include/net/inet_common.h
index 4a92423eefa509b27d8caf75474406fe03868b04..279f83591971bd886e78e1b20e4a5c29051fc563 100644 (file)
--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -41,7 +41,7 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len,
 
 static inline void inet_ctl_sock_destroy(struct sock *sk)
 {
-       sk_release_kernel(sk);
+       sock_release(sk->sk_socket);
 }
 
 #endif

diff --git a/include/net/sock.h b/include/net/sock.h
index d8dcf91732b026b2be612194314fcb26751c874d..9e6b2c0b47410f58136609b23775b448f15b4782 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -184,6 +184,7 @@ struct sock_common {
        unsigned char           skc_reuse:4;
        unsigned char           skc_reuseport:1;
        unsigned char           skc_ipv6only:1;
+       unsigned char           skc_net_refcnt:1;
        int                     skc_bound_dev_if;
        union {
                struct hlist_node       skc_bind_node;
@@ -323,6 +324,7 @@ struct sock {
 #define sk_reuse               __sk_common.skc_reuse
 #define sk_reuseport           __sk_common.skc_reuseport
 #define sk_ipv6only            __sk_common.skc_ipv6only
+#define sk_net_refcnt          __sk_common.skc_net_refcnt
 #define sk_bound_dev_if                __sk_common.skc_bound_dev_if
 #define sk_bind_node           __sk_common.skc_bind_node
 #define sk_prot                        __sk_common.skc_prot

diff --git a/net/core/sock.c b/net/core/sock.c
index cbc3789b830c74d3d683a1615f83721a5d256075..9e8968e9ebeb3ff19aab63d99e558f919bb5609d 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1412,7 +1412,10 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
                 */
                sk->sk_prot = sk->sk_prot_creator = prot;
                sock_lock_init(sk);
-               sock_net_set(sk, get_net(net));
+               sk->sk_net_refcnt = kern ? 0 : 1;
+               if (likely(sk->sk_net_refcnt))
+                       get_net(net);
+               sock_net_set(sk, net);
                atomic_set(&sk->sk_wmem_alloc, 1);
 
                sock_update_classid(sk);
@@ -1446,7 +1449,8 @@ static void __sk_free(struct sock *sk)
        if (sk->sk_peer_cred)
                put_cred(sk->sk_peer_cred);
        put_pid(sk->sk_peer_pid);
-       put_net(sock_net(sk));
+       if (likely(sk->sk_net_refcnt))
+               put_net(sock_net(sk));
        sk_prot_free(sk->sk_prot_creator, sk);
 }
 

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index e2dd9cb99d61b128d8491bc4c7cd878b9f11a5f9..235d36afece3b53f5fd5f795f28d15f6f2a79ab6 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1430,7 +1430,7 @@ int inet_ctl_sock_create(struct sock **sk, unsigned short family,
                         struct net *net)
 {
        struct socket *sock;
-       int rc = sock_create_kern(&init_net, family, type, protocol, &sock);
+       int rc = sock_create_kern(net, family, type, protocol, &sock);
 
        if (rc == 0) {
                *sk = sock->sk;
@@ -1440,8 +1440,6 @@ int inet_ctl_sock_create(struct sock **sk, unsigned short family,
                 * we do not wish this socket to see incoming packets.
                 */
                (*sk)->sk_prot->unhash(*sk);
-
-               sk_change_net(*sk, net);
        }
        return rc;
 }

diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 4e2837476967e55016147850049d37e754f343d2..933ea903f7b8fffc02fb7f82deab9c98c35e2daf 100644 (file)
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -15,12 +15,10 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
        struct socket *sock = NULL;
        struct sockaddr_in udp_addr;
 
-       err = sock_create_kern(&init_net, AF_INET, SOCK_DGRAM, 0, &sock);
+       err = sock_create_kern(net, AF_INET, SOCK_DGRAM, 0, &sock);
        if (err < 0)
                goto error;
 
-       sk_change_net(sock->sk, net);
-
        udp_addr.sin_family = AF_INET;
        udp_addr.sin_addr = cfg->local_ip;
        udp_addr.sin_port = cfg->local_udp_port;
@@ -47,7 +45,7 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
 error:
        if (sock) {
                kernel_sock_shutdown(sock, SHUT_RDWR);
-               sk_release_kernel(sock->sk);
+               sock_release(sock);
        }
        *sockp = NULL;
        return err;
@@ -101,7 +99,7 @@ void udp_tunnel_sock_release(struct socket *sock)
 {
        rcu_assign_sk_user_data(sock->sk, NULL);
        kernel_sock_shutdown(sock, SHUT_RDWR);
-       sk_release_kernel(sock->sk);
+       sock_release(sock);
 }
 EXPORT_SYMBOL_GPL(udp_tunnel_sock_release);
 

diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index 478576b6121439cfa45f6b21a4a7c42558a738d3..e1a1136bda7c8f15e589c92e7ea752ddceee70f4 100644 (file)
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -19,12 +19,10 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
        int err;
        struct socket *sock = NULL;
 
-       err = sock_create_kern(&init_net, AF_INET6, SOCK_DGRAM, 0, &sock);
+       err = sock_create_kern(net, AF_INET6, SOCK_DGRAM, 0, &sock);
        if (err < 0)
                goto error;
 
-       sk_change_net(sock->sk, net);
-
        udp6_addr.sin6_family = AF_INET6;
        memcpy(&udp6_addr.sin6_addr, &cfg->local_ip6,
               sizeof(udp6_addr.sin6_addr));
@@ -55,7 +53,7 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
 error:
        if (sock) {
                kernel_sock_shutdown(sock, SHUT_RDWR);
-               sk_release_kernel(sock->sk);
+               sock_release(sock);
        }
        *sockp = NULL;
        return err;

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index ae513a2fe7f3408332e6b99e34370da7a64fe02e..f6b090df3930d32dc1fda0c8069ad1f7b3246d41 100644 (file)
--- 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;
        }
 

diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 2e9a5b5d123903d0171e3ba84ab3cf15515c35fd..b08ba9538d121bad95ab9aa579b2b37523f57dc2 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -1457,18 +1457,12 @@ static struct socket *make_send_sock(struct net *net, int id)
        struct socket *sock;
        int result;
 
-       /* First create a socket move it to right name space later */
-       result = sock_create_kern(&init_net, PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+       /* First create a socket */
+       result = sock_create_kern(net, PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
        if (result < 0) {
                pr_err("Error during creation of socket; terminating\n");
                return ERR_PTR(result);
        }
-       /*
-        * Kernel sockets that are a part of a namespace, should not
-        * hold a reference to a namespace in order to allow to stop it.
-        * After sk_change_net should be released using sk_release_kernel.
-        */
-       sk_change_net(sock->sk, net);
        result = set_mcast_if(sock->sk, ipvs->master_mcast_ifn);
        if (result < 0) {
                pr_err("Error setting outbound mcast interface\n");
@@ -1497,7 +1491,7 @@ static struct socket *make_send_sock(struct net *net, int id)
        return sock;
 
 error:
-       sk_release_kernel(sock->sk);
+       sock_release(sock);
        return ERR_PTR(result);
 }
 
@@ -1518,17 +1512,11 @@ static struct socket *make_receive_sock(struct net *net, int id)
        int result;
 
        /* First create a socket */
-       result = sock_create_kern(&init_net, PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+       result = sock_create_kern(net, PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
        if (result < 0) {
                pr_err("Error during creation of socket; terminating\n");
                return ERR_PTR(result);
        }
-       /*
-        * Kernel sockets that are a part of a namespace, should not
-        * hold a reference to a namespace in order to allow to stop it.
-        * After sk_change_net should be released using sk_release_kernel.
-        */
-       sk_change_net(sock->sk, net);
        /* it is equivalent to the REUSEADDR option in user-space */
        sock->sk->sk_reuse = SK_CAN_REUSE;
        result = sysctl_sync_sock_size(ipvs);
@@ -1554,7 +1542,7 @@ static struct socket *make_receive_sock(struct net *net, int id)
        return sock;
 
 error:
-       sk_release_kernel(sock->sk);
+       sock_release(sock);
        return ERR_PTR(result);
 }
 
@@ -1692,7 +1680,7 @@ done:
                ip_vs_sync_buff_release(sb);
 
        /* release the sending multicast socket */
-       sk_release_kernel(tinfo->sock->sk);
+       sock_release(tinfo->sock);
        kfree(tinfo);
 
        return 0;
@@ -1729,7 +1717,7 @@ static int sync_thread_backup(void *data)
        }
 
        /* release the sending multicast socket */
-       sk_release_kernel(tinfo->sock->sk);
+       sock_release(tinfo->sock);
        kfree(tinfo->buf);
        kfree(tinfo);
 
@@ -1854,11 +1842,11 @@ int start_sync_thread(struct net *net, int state, char *mcast_ifn, __u8 syncid)
        return 0;
 
 outsocket:
-       sk_release_kernel(sock->sk);
+       sock_release(sock);
 
 outtinfo:
        if (tinfo) {
-               sk_release_kernel(tinfo->sock->sk);
+               sock_release(tinfo->sock);
                kfree(tinfo->buf);
                kfree(tinfo);
        }