[TCP]: default congestion control menu

Change how default TCP congestion control is chosen. Don't just use
last installed module, instead allow selection during configuration,
and make sure and use the default regardless of load order.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 1650b64415aa8a41aba0a81fcb3b0d569285391a..1bbc3689cd8a8642fda5a1c70053a6bcc476df73 100644 (file)
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -448,7 +448,7 @@ config INET_TCP_DIAG
        depends on INET_DIAG
        def_tristate INET_DIAG
 
-config TCP_CONG_ADVANCED
+menuconfig TCP_CONG_ADVANCED
        bool "TCP: advanced congestion control"
        ---help---
          Support for selection of various TCP congestion control
@@ -459,9 +459,7 @@ config TCP_CONG_ADVANCED
 
          If unsure, say N.
 
-# TCP Reno is builtin (required as fallback)
-menu "TCP congestion control"
-       depends on TCP_CONG_ADVANCED
+if TCP_CONG_ADVANCED
 
 config TCP_CONG_BIC
        tristate "Binary Increase Congestion (BIC) control"
@@ -574,12 +572,49 @@ config TCP_CONG_VENO
        loss packets.
        See http://www.ntu.edu.sg/home5/ZHOU0022/papers/CPFu03a.pdf
 
-endmenu
+choice
+       prompt "Default TCP congestion control"
+       default DEFAULT_BIC
+       help
+         Select the TCP congestion control that will be used by default
+         for all connections.
+
+       config DEFAULT_BIC
+               bool "Bic" if TCP_CONG_BIC=y
+
+       config DEFAULT_CUBIC
+               bool "Cubic" if TCP_CONG_CUBIC=y
+
+       config DEFAULT_HTCP
+               bool "Htcp" if TCP_CONG_HTCP=y
+
+       config DEFAULT_VEGAS
+               bool "Vegas" if TCP_CONG_VEGAS=y
+
+       config DEFAULT_WESTWOOD
+               bool "Westwood" if TCP_CONG_WESTWOOD=y
+
+       config DEFAULT_RENO
+               bool "Reno"
+
+endchoice
+
+endif
 
 config TCP_CONG_BIC
        tristate
        depends on !TCP_CONG_ADVANCED
        default y
 
+config DEFAULT_TCP_CONG
+       string
+       default "bic" if DEFAULT_BIC
+       default "cubic" if DEFAULT_CUBIC
+       default "htcp" if DEFAULT_HTCP
+       default "vegas" if DEFAULT_VEGAS
+       default "westwood" if DEFAULT_WESTWOOD
+       default "reno" if DEFAULT_RENO
+       default "bic"
+
 source "net/ipv4/ipvs/Kconfig"
 

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 19b2071ff319bf256ae048f104dbd9a16999b98b..e82a5be894b51ca523697910daafb41c9a823e9d 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -129,6 +129,12 @@ static int sysctl_tcp_congestion_control(ctl_table *table, int __user *name,
        return ret;
 }
 
+static int __init tcp_congestion_default(void)
+{
+       return tcp_set_default_congestion_control(CONFIG_DEFAULT_TCP_CONG);
+}
+
+late_initcall(tcp_congestion_default);
 
 ctl_table ipv4_table[] = {
         {

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 7ff2e4273a7c41adf27c9174cbd22ce52cfd6b78..af0aca1e6be612ee100cc99bca70102ed644a3eb 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -48,7 +48,7 @@ int tcp_register_congestion_control(struct tcp_congestion_ops *ca)
                printk(KERN_NOTICE "TCP %s already registered\n", ca->name);
                ret = -EEXIST;
        } else {
-               list_add_rcu(&ca->list, &tcp_cong_list);
+               list_add_tail_rcu(&ca->list, &tcp_cong_list);
                printk(KERN_INFO "TCP %s registered\n", ca->name);
        }
        spin_unlock(&tcp_cong_list_lock);