1 files changed, 24 insertions, 31 deletions

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 7b09d8b49fa5..b1c5970d47a1 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -74,24 +74,34 @@ void tcp_unregister_congestion_control(struct tcp_congestion_ops *ca)
 EXPORT_SYMBOL_GPL(tcp_unregister_congestion_control);
 
 /* Assign choice of congestion control. */
-void tcp_init_congestion_control(struct sock *sk)
+void tcp_assign_congestion_control(struct sock *sk)
 {
         struct inet_connection_sock *icsk = inet_csk(sk);
         struct tcp_congestion_ops *ca;
 
-        /* if no choice made yet assign the current value set as default */
-        if (icsk->icsk_ca_ops == &tcp_init_congestion_ops) {
-                rcu_read_lock();
-                list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
-                        if (try_module_get(ca->owner)) {
-                                icsk->icsk_ca_ops = ca;
-                                break;
-                        }
-
-                        /* fallback to next available */
+        rcu_read_lock();
+        list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
+                if (likely(try_module_get(ca->owner))) {
+                        icsk->icsk_ca_ops = ca;
+                        goto out;
                 }
-                rcu_read_unlock();
+                /* Fallback to next available. The last really
+                 * guaranteed fallback is Reno from this list.
+                 */
         }
+out:
+        rcu_read_unlock();
+
+        /* Clear out private data before diag gets it and
+         * the ca has not been initialized.
+         */
+        if (ca->get_info)
+                memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
+}
+
+void tcp_init_congestion_control(struct sock *sk)
+{
+        const struct inet_connection_sock *icsk = inet_csk(sk);
 
         if (icsk->icsk_ca_ops->init)
                 icsk->icsk_ca_ops->init(sk);
@@ -142,7 +152,6 @@ static int __init tcp_congestion_default(void)
 }
 late_initcall(tcp_congestion_default);
 
-
 /* Build string with list of available congestion control values */
 void tcp_get_available_congestion_control(char *buf, size_t maxlen)
 {
@@ -154,7 +163,6 @@ void tcp_get_available_congestion_control(char *buf, size_t maxlen)
                 offs += snprintf(buf + offs, maxlen - offs,
                                  "%s%s",
                                  offs == 0 ? "" : " ", ca->name);
-
         }
         rcu_read_unlock();
 }
@@ -186,7 +194,6 @@ void tcp_get_allowed_congestion_control(char *buf, size_t maxlen)
                 offs += snprintf(buf + offs, maxlen - offs,
                                  "%s%s",
                                  offs == 0 ? "" : " ", ca->name);
-
         }
         rcu_read_unlock();
 }
@@ -230,7 +237,6 @@ out:
         return ret;
 }
 
-
 /* Change congestion control for socket */
 int tcp_set_congestion_control(struct sock *sk, const char *name)
 {
@@ -285,15 +291,13 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
  * ABC caps N to 2. Slow start exits when cwnd grows over ssthresh and
  * returns the leftover acks to adjust cwnd in congestion avoidance mode.
  */
-int tcp_slow_start(struct tcp_sock *tp, u32 acked)
+void tcp_slow_start(struct tcp_sock *tp, u32 acked)
 {
         u32 cwnd = tp->snd_cwnd + acked;
 
         if (cwnd > tp->snd_ssthresh)
                 cwnd = tp->snd_ssthresh + 1;
-        acked -= cwnd - tp->snd_cwnd;
         tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp);
-        return acked;
 }
 EXPORT_SYMBOL_GPL(tcp_slow_start);
 
@@ -337,6 +341,7 @@ EXPORT_SYMBOL_GPL(tcp_reno_cong_avoid);
 u32 tcp_reno_ssthresh(struct sock *sk)
 {
         const struct tcp_sock *tp = tcp_sk(sk);
+
         return max(tp->snd_cwnd >> 1U, 2U);
 }
 EXPORT_SYMBOL_GPL(tcp_reno_ssthresh);
@@ -348,15 +353,3 @@ struct tcp_congestion_ops tcp_reno = {
         .ssthresh       = tcp_reno_ssthresh,
         .cong_avoid     = tcp_reno_cong_avoid,
 };
-
-/* Initial congestion control used (until SYN)
- * really reno under another name so we can tell difference
- * during tcp_set_default_congestion_control
- */
-struct tcp_congestion_ops tcp_init_congestion_ops  = {
-        .name           = "",
-        .owner          = THIS_MODULE,
-        .ssthresh       = tcp_reno_ssthresh,
-        .cong_avoid     = tcp_reno_cong_avoid,
-};
-EXPORT_SYMBOL_GPL(tcp_init_congestion_ops);