1 files changed, 21 insertions, 3 deletions

diff --git a/net/mac80211/ieee80211_rate.c b/net/mac80211/ieee80211_rate.c
index 93abb8fff141..7254bd609839 100644
--- a/net/mac80211/ieee80211_rate.c
+++ b/net/mac80211/ieee80211_rate.c
@@ -25,13 +25,25 @@ int ieee80211_rate_control_register(struct rate_control_ops *ops)
 {
         struct rate_control_alg *alg;
 
+        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);
 
@@ -61,9 +73,12 @@ ieee80211_try_rate_control_ops_get(const char *name)
         struct rate_control_alg *alg;
         struct rate_control_ops *ops = NULL;
 
+        if (!name)
+                return NULL;
+
         mutex_lock(&rate_ctrl_mutex);
         list_for_each_entry(alg, &rate_ctrl_algs, list) {
-                if (!name || !strcmp(alg->ops->name, name))
+                if (!strcmp(alg->ops->name, name))
                         if (try_module_get(alg->ops->module)) {
                                 ops = alg->ops;
                                 break;
@@ -80,9 +95,12 @@ ieee80211_rate_control_ops_get(const char *name)
 {
         struct rate_control_ops *ops;
 
+        if (!name)
+                name = "simple";
+
         ops = ieee80211_try_rate_control_ops_get(name);
         if (!ops) {
-                request_module("rc80211_%s", name ? name : "default");
+                request_module("rc80211_%s", name);
                 ops = ieee80211_try_rate_control_ops_get(name);
         }
         return ops;