mac80211: fix TX status cookie in HW offload case

When the off-channel TX is done with remain-on-channel
offloaded to hardware, the reported cookie is wrong as
in that case we shouldn't use the SKB as the cookie but
need to instead use the corresponding r-o-c cookie
(XOR'ed with 2 to prevent API mismatches).

Fix this by keeping track of the hw_roc_skb pointer
just for the status processing and use the correct
cookie to report in this case. We can't use the
hw_roc_skb pointer itself because it is NULL'ed when
the frame is transmitted to prevent it being used
twice.

This fixes a bug where the P2P state machine in the
supplicant gets stuck because it never gets a correct
result for its transmitted frame.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 38a7972..071ac95 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -323,6 +323,7 @@
 
 	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
 		struct ieee80211_work *wk;
+		u64 cookie = (unsigned long)skb;
 
 		rcu_read_lock();
 		list_for_each_entry_rcu(wk, &local->work_list, list) {
@@ -334,8 +335,12 @@
 			break;
 		}
 		rcu_read_unlock();
+		if (local->hw_roc_skb_for_status == skb) {
+			cookie = local->hw_roc_cookie ^ 2;
+			local->hw_roc_skb_for_status = NULL;
+		}
 		cfg80211_mgmt_tx_status(
-			skb->dev, (unsigned long) skb, skb->data, skb->len,
+			skb->dev, cookie, skb->data, skb->len,
 			!!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
 	}