regulatory: fix uevent

The uevent callback doesn't protect its access to
last_request, which now causes a warning since
the conversion to get_last_request(). Fix this by
allowing to use RCU protection for last_request.

Reported-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 13 insertions, 6 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 0b35de001937..2193f62bb8ae 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -140,8 +140,8 @@ static void rcu_free_regdom(const struct ieee80211_regdomain *r)
 
 static struct regulatory_request *get_last_request(void)
 {
-        return rcu_dereference_protected(last_request,
-                                         lockdep_is_held(&reg_mutex));
+        return rcu_dereference_check(last_request,
+                                     lockdep_is_held(&reg_mutex));
 }
 
 /* Used to queue up regulatory hints */
@@ -2250,14 +2250,21 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 #ifdef CONFIG_HOTPLUG
 int reg_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-        struct regulatory_request *lr = get_last_request();
+        struct regulatory_request *lr;
+        u8 alpha2[2];
+        bool add = false;
 
+        rcu_read_lock();
+        lr = get_last_request();
         if (lr && !lr->processed) {
-                if (add_uevent_var(env, "COUNTRY=%c%c",
-                                   lr->alpha2[0], lr->alpha2[1]))
-                        return -ENOMEM;
+                memcpy(alpha2, lr->alpha2, 2);
+                add = true;
         }
+        rcu_read_unlock();
 
+        if (add)
+                return add_uevent_var(env, "COUNTRY=%c%c",
+                                      alpha2[0], alpha2[1]);
         return 0;
 }
 #else