From: Johannes Berg <johannes@sipsolutions.net>
Date: Sun, 28 Oct 2007 13:49:33 +0000 (+0100)
Subject: mac80211: don't allow registering the same rate control twice
X-Git-Tag: v2.6.24-rc3~155^2~17
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=999acd9c339a761a18d625b13001612ac396ee00;p=linux-2.6

mac80211: don't allow registering the same rate control twice

Previously, mac80211 would allow registering the same rate control
algorithm twice. This is a programming error in the registration
and should not happen; additionally the second version could never
be selected. Disallow this and warn about it.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---

diff --git a/net/mac80211/ieee80211_rate.c b/net/mac80211/ieee80211_rate.c
index e4bd848155..7254bd6098 100644
--- a/net/mac80211/ieee80211_rate.c
+++ b/net/mac80211/ieee80211_rate.c
@@ -28,13 +28,22 @@ int ieee80211_rate_control_register(struct rate_control_ops *ops)
 	if (!ops->name)
 		return -EINVAL;
 
+	mutex_lock(&rate_ctrl_mutex);
+	list_for_each_entry(alg, &rate_ctrl_algs, list) {
+		if (!strcmp(alg->ops->name, ops->name)) {
+			/* don't register an algorithm twice */
+			WARN_ON(1);
+			return -EALREADY;
+		}
+	}
+
 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
 	if (alg == NULL) {
+		mutex_unlock(&rate_ctrl_mutex);
 		return -ENOMEM;
 	}
 	alg->ops = ops;
 
-	mutex_lock(&rate_ctrl_mutex);
 	list_add_tail(&alg->list, &rate_ctrl_algs);
 	mutex_unlock(&rate_ctrl_mutex);