iwlwifi: mvm: change state when queueing agg start work

Add a new state to enum iwl_mvm_agg_state, which is used between
queueing the work that starts tx aggregations and actually starting that
work (changing to state IWL_AGG_STARTING).
This solves a race where ieee80211_start_tx_ba_session is called a
second time, before the work queued by the first run has a chance to
change the agg_state. In this case the second call to
ieee80211_start_tx_ba_session returns an error, and the fallback is to
abort the ba session start.

Fixes: 482e48440a0e ("iwlwifi: mvm: change open and close criteria of a BA session")
Signed-off-by: Naftali Goldstein <naftali.goldstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
index ba7bd04..0fe723c 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
@@ -661,7 +661,8 @@ static void rs_tl_turn_on_agg(struct iwl_mvm *mvm, struct iwl_mvm_sta *mvmsta,
 	    (lq_sta->tx_agg_tid_en & BIT(tid)) &&
 	    (tid_data->tx_count_last >= IWL_MVM_RS_AGG_START_THRESHOLD)) {
 		IWL_DEBUG_RATE(mvm, "try to aggregate tid %d\n", tid);
-		rs_tl_turn_on_agg_for_tid(mvm, lq_sta, tid, sta);
+		if (rs_tl_turn_on_agg_for_tid(mvm, lq_sta, tid, sta) == 0)
+			tid_data->state = IWL_AGG_QUEUED;
 	}
 }