regulatory: use RCU in regulatory_hint_11d()

Since it just does a quick check of the last regulatory
request, the function doesn't have to hold the reg mutex
but can use RCU instead.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 16 insertions, 14 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index e76559618588..17e5eccb42c8 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -1715,20 +1715,18 @@ void regulatory_hint_11d(struct wiphy *wiphy, enum ieee80211_band band,
 {
         char alpha2[2];
         enum environment_cap env = ENVIRON_ANY;
-        struct regulatory_request *request, *lr;
-
-        mutex_lock(&reg_mutex);
-        lr = get_last_request();
-
-        if (unlikely(!lr))
-                goto out;
+        struct regulatory_request *request = NULL, *lr;
 
         /* IE len must be evenly divisible by 2 */
         if (country_ie_len & 0x01)
-                goto out;
+                return;
 
         if (country_ie_len < IEEE80211_COUNTRY_IE_MIN_LEN)
-                goto out;
+                return;
+
+        request = kzalloc(sizeof(*request), GFP_KERNEL);
+        if (!request)
+                return;
 
         alpha2[0] = country_ie[0];
         alpha2[1] = country_ie[1];
@@ -1738,6 +1736,12 @@ void regulatory_hint_11d(struct wiphy *wiphy, enum ieee80211_band band,
         else if (country_ie[2] == 'O')
                 env = ENVIRON_OUTDOOR;
 
+        rcu_read_lock();
+        lr = get_last_request();
+
+        if (unlikely(!lr))
+                goto out;
+
         /*
          * We will run this only upon a successful connection on cfg80211.
          * We leave conflict resolution to the workqueue, where can hold
@@ -1747,10 +1751,6 @@ void regulatory_hint_11d(struct wiphy *wiphy, enum ieee80211_band band,
             lr->wiphy_idx != WIPHY_IDX_INVALID)
                 goto out;
 
-        request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL);
-        if (!request)
-                goto out;
-
         request->wiphy_idx = get_wiphy_idx(wiphy);
         request->alpha2[0] = alpha2[0];
         request->alpha2[1] = alpha2[1];
@@ -1758,8 +1758,10 @@ void regulatory_hint_11d(struct wiphy *wiphy, enum ieee80211_band band,
         request->country_ie_env = env;
 
         queue_regulatory_request(request);
+        request = NULL;
 out:
-        mutex_unlock(&reg_mutex);
+        kfree(request);
+        rcu_read_unlock();
 }
 
 static void restore_alpha2(char *alpha2, bool reset_user)