mac80211: sparse RCU annotations

This adds sparse RCU annotations to most of
mac80211, only the mesh code remains to be
done.

Due the the previous patches, the annotations
are pretty simple. The only thing that this
actually changes is removing the RCU usage of
key->sta in debugfs since this pointer isn't
actually an RCU-managed pointer (it only has
a single assignment done before the key even
goes live). As that is otherwise harmless, I
decided to make it part of this patch.

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

1 files changed, 8 insertions, 3 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index b81860c94698..421eaa6b0c2b 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -662,12 +662,16 @@ static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
         int tx_last_beacon, len = req->len;
         struct sk_buff *skb;
         struct ieee80211_mgmt *resp;
+        struct sk_buff *presp;
         u8 *pos, *end;
 
         lockdep_assert_held(&ifibss->mtx);
 
+        presp = rcu_dereference_protected(ifibss->presp,
+                                          lockdep_is_held(&ifibss->mtx));
+
         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
-            len < 24 + 2 || !ifibss->presp)
+            len < 24 + 2 || !presp)
                 return;
 
         tx_last_beacon = drv_tx_last_beacon(local);
@@ -705,7 +709,7 @@ static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
         }
 
         /* Reply with ProbeResp */
-        skb = skb_copy(ifibss->presp, GFP_KERNEL);
+        skb = skb_copy(presp, GFP_KERNEL);
         if (!skb)
                 return;
 
@@ -985,7 +989,8 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 
         /* remove beacon */
         kfree(sdata->u.ibss.ie);
-        skb = sdata->u.ibss.presp;
+        skb = rcu_dereference_protected(sdata->u.ibss.presp,
+                                        lockdep_is_held(&sdata->u.ibss.mtx));
         rcu_assign_pointer(sdata->u.ibss.presp, NULL);
         sdata->vif.bss_conf.ibss_joined = false;
         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |