bpf: Add support for changing congestion control

[platform/kernel/linux-rpi.git] / net / ipv4 / tcp_cong.c

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 324c9bc..fde983f 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -189,8 +189,8 @@ void tcp_init_congestion_control(struct sock *sk)
                INET_ECN_dontxmit(sk);
 }
 
-static void tcp_reinit_congestion_control(struct sock *sk,
-                                         const struct tcp_congestion_ops *ca)
+void tcp_reinit_congestion_control(struct sock *sk,
+                                  const struct tcp_congestion_ops *ca)
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
 
@@ -333,8 +333,12 @@ out:
        return ret;
 }
 
-/* Change congestion control for socket */
-int tcp_set_congestion_control(struct sock *sk, const char *name)
+/* Change congestion control for socket. If load is false, then it is the
+ * responsibility of the caller to call tcp_init_congestion_control or
+ * tcp_reinit_congestion_control (if the current congestion control was
+ * already initialized.
+ */
+int tcp_set_congestion_control(struct sock *sk, const char *name, bool load)
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
        const struct tcp_congestion_ops *ca;
@@ -344,21 +348,29 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
                return -EPERM;
 
        rcu_read_lock();
-       ca = __tcp_ca_find_autoload(name);
+       if (!load)
+               ca = tcp_ca_find(name);
+       else
+               ca = __tcp_ca_find_autoload(name);
        /* No change asking for existing value */
        if (ca == icsk->icsk_ca_ops) {
                icsk->icsk_ca_setsockopt = 1;
                goto out;
        }
-       if (!ca)
+       if (!ca) {
                err = -ENOENT;
-       else if (!((ca->flags & TCP_CONG_NON_RESTRICTED) ||
-                  ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)))
+       } else if (!load) {
+               icsk->icsk_ca_ops = ca;
+               if (!try_module_get(ca->owner))
+                       err = -EBUSY;
+       } else if (!((ca->flags & TCP_CONG_NON_RESTRICTED) ||
+                    ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))) {
                err = -EPERM;
-       else if (!try_module_get(ca->owner))
+       } else if (!try_module_get(ca->owner)) {
                err = -EBUSY;
-       else
+       } else {
                tcp_reinit_congestion_control(sk, ca);
+       }
  out:
        rcu_read_unlock();
        return err;