From 35bfbc94070e480f350c868abc4ff9f77e7f2051 Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <shemminger@osdl.org>
Date: Thu, 9 Nov 2006 16:36:36 -0800
Subject: [PATCH] [TCP]: Allow autoloading of congestion control via
setsockopt.
If user has permision to load modules, then autoload then attempt
autoload of TCP congestion module.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/tcp_cong.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 343d6197c92e..5ca7723d0798 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -113,7 +113,7 @@ int tcp_set_default_congestion_control(const char *name)
spin_lock(&tcp_cong_list_lock);
ca = tcp_ca_find(name);
#ifdef CONFIG_KMOD
- if (!ca) {
+ if (!ca && capable(CAP_SYS_MODULE)) {
spin_unlock(&tcp_cong_list_lock);
request_module("tcp_%s", name);
@@ -236,9 +236,19 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
rcu_read_lock();
ca = tcp_ca_find(name);
+ /* no change asking for existing value */
if (ca == icsk->icsk_ca_ops)
goto out;
+#ifdef CONFIG_KMOD
+ /* not found attempt to autoload module */
+ if (!ca && capable(CAP_SYS_MODULE)) {
+ rcu_read_unlock();
+ request_module("tcp_%s", name);
+ rcu_read_lock();
+ ca = tcp_ca_find(name);
+ }
+#endif
if (!ca)
err = -ENOENT;
--
2.30.9