1 files changed, 14 insertions, 5 deletions

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index fde983f6376b..421ea1b918da 100644
--- 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);
 }
 
-void tcp_reinit_congestion_control(struct sock *sk,
-                                   const struct tcp_congestion_ops *ca)
+static void tcp_reinit_congestion_control(struct sock *sk,
+                                          const struct tcp_congestion_ops *ca)
 {
         struct inet_connection_sock *icsk = inet_csk(sk);
 
@@ -338,7 +338,7 @@ out:
  * 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)
+int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, bool reinit)
 {
         struct inet_connection_sock *icsk = inet_csk(sk);
         const struct tcp_congestion_ops *ca;
@@ -360,9 +360,18 @@ int tcp_set_congestion_control(struct sock *sk, const char *name, bool load)
         if (!ca) {
                 err = -ENOENT;
         } else if (!load) {
-                icsk->icsk_ca_ops = ca;
-                if (!try_module_get(ca->owner))
+                const struct tcp_congestion_ops *old_ca = icsk->icsk_ca_ops;
+
+                if (try_module_get(ca->owner)) {
+                        if (reinit) {
+                                tcp_reinit_congestion_control(sk, ca);
+                        } else {
+                                icsk->icsk_ca_ops = ca;
+                                module_put(old_ca->owner);
+                        }
+                } else {
                         err = -EBUSY;
+                }
         } else if (!((ca->flags & TCP_CONG_NON_RESTRICTED) ||
                      ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))) {
                 err = -EPERM;