4 files changed, 52 insertions, 39 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
index 565522466eba..b55b1b17f4d1 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -732,7 +732,10 @@ void iwl_mvm_mac_itxq_xmit(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
 
 	rcu_read_lock();
 	do {
-		while (likely(!mvmtxq->stopped &&
+		while (likely(!test_bit(IWL_MVM_TXQ_STATE_STOP_FULL,
+					&mvmtxq->state) &&
+			      !test_bit(IWL_MVM_TXQ_STATE_STOP_REDIRECT,
+					&mvmtxq->state) &&
 			      !test_bit(IWL_MVM_STATUS_IN_D3, &mvm->status))) {
 			skb = ieee80211_tx_dequeue(hw, txq);
 
@@ -757,42 +760,25 @@ static void iwl_mvm_mac_wake_tx_queue(struct ieee80211_hw *hw,
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
 	struct iwl_mvm_txq *mvmtxq = iwl_mvm_txq_from_mac80211(txq);
 
-	/*
-	 * Please note that racing is handled very carefully here:
-	 * mvmtxq->txq_id is updated during allocation, and mvmtxq->list is
-	 * deleted afterwards.
-	 * This means that if:
-	 * mvmtxq->txq_id != INVALID_QUEUE && list_empty(&mvmtxq->list):
-	 *	queue is allocated and we can TX.
-	 * mvmtxq->txq_id != INVALID_QUEUE && !list_empty(&mvmtxq->list):
-	 *	a race, should defer the frame.
-	 * mvmtxq->txq_id == INVALID_QUEUE && list_empty(&mvmtxq->list):
-	 *	need to allocate the queue and defer the frame.
-	 * mvmtxq->txq_id == INVALID_QUEUE && !list_empty(&mvmtxq->list):
-	 *	queue is already scheduled for allocation, no need to allocate,
-	 *	should defer the frame.
-	 */
-
-	/* If the queue is allocated TX and return. */
-	if (!txq->sta || mvmtxq->txq_id != IWL_MVM_INVALID_QUEUE) {
-		/*
-		 * Check that list is empty to avoid a race where txq_id is
-		 * already updated, but the queue allocation work wasn't
-		 * finished
-		 */
-		if (unlikely(txq->sta && !list_empty(&mvmtxq->list)))
-			return;
-
+	if (likely(test_bit(IWL_MVM_TXQ_STATE_READY, &mvmtxq->state)) ||
+	    !txq->sta) {
 		iwl_mvm_mac_itxq_xmit(hw, txq);
 		return;
 	}
 
-	/* The list is being deleted only after the queue is fully allocated. */
-	if (!list_empty(&mvmtxq->list))
-		return;
+	/* iwl_mvm_mac_itxq_xmit() will later be called by the worker
+	 * to handle any packets we leave on the txq now
+	 */
 
-	list_add_tail(&mvmtxq->list, &mvm->add_stream_txqs);
-	schedule_work(&mvm->add_stream_wk);
+	spin_lock_bh(&mvm->add_stream_lock);
+	/* The list is being deleted only after the queue is fully allocated. */
+	if (list_empty(&mvmtxq->list) &&
+	    /* recheck under lock */
+	    !test_bit(IWL_MVM_TXQ_STATE_READY, &mvmtxq->state)) {
+		list_add_tail(&mvmtxq->list, &mvm->add_stream_txqs);
+		schedule_work(&mvm->add_stream_wk);
+	}
+	spin_unlock_bh(&mvm->add_stream_lock);
 }
 
 #define CHECK_BA_TRIGGER(_mvm, _trig, _tid_bm, _tid, _fmt...)		\
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
index 90bc95d96a78..f307c345dfa0 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
@@ -729,7 +729,10 @@ struct iwl_mvm_txq {
 	struct list_head list;
 	u16 txq_id;
 	atomic_t tx_request;
-	bool stopped;
+#define IWL_MVM_TXQ_STATE_STOP_FULL	0
+#define IWL_MVM_TXQ_STATE_STOP_REDIRECT	1
+#define IWL_MVM_TXQ_STATE_READY		2
+	unsigned long state;
 };
 
 static inline struct iwl_mvm_txq *
@@ -827,6 +830,7 @@ struct iwl_mvm {
 		struct iwl_mvm_tvqm_txq_info tvqm_info[IWL_MAX_TVQM_QUEUES];
 	};
 	struct work_struct add_stream_wk; /* To add streams to queues */
+	spinlock_t add_stream_lock;
 
 	const char *nvm_file_name;
 	struct iwl_nvm_data *nvm_data;
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
index f4e9446d9dc2..9711841bb456 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
@@ -1195,6 +1195,7 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 	INIT_DELAYED_WORK(&mvm->scan_timeout_dwork, iwl_mvm_scan_timeout_wk);
 	INIT_WORK(&mvm->add_stream_wk, iwl_mvm_add_new_dqa_stream_wk);
 	INIT_LIST_HEAD(&mvm->add_stream_txqs);
+	spin_lock_init(&mvm->add_stream_lock);
 
 	init_waitqueue_head(&mvm->rx_sync_waitq);
 
@@ -1691,7 +1692,10 @@ static void iwl_mvm_queue_state_change(struct iwl_op_mode *op_mode,
 
 		txq = sta->txq[tid];
 		mvmtxq = iwl_mvm_txq_from_mac80211(txq);
-		mvmtxq->stopped = !start;
+		if (start)
+			clear_bit(IWL_MVM_TXQ_STATE_STOP_FULL, &mvmtxq->state);
+		else
+			set_bit(IWL_MVM_TXQ_STATE_STOP_FULL, &mvmtxq->state);
 
 		if (start && mvmsta->sta_state != IEEE80211_STA_NOTEXIST)
 			iwl_mvm_mac_itxq_xmit(mvm->hw, txq);
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
index 69634fb82a9b..9caae77995ca 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
@@ -384,8 +384,11 @@ static int iwl_mvm_disable_txq(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 		struct iwl_mvm_txq *mvmtxq =
 			iwl_mvm_txq_from_tid(sta, tid);
 
-		mvmtxq->txq_id = IWL_MVM_INVALID_QUEUE;
+		spin_lock_bh(&mvm->add_stream_lock);
 		list_del_init(&mvmtxq->list);
+		clear_bit(IWL_MVM_TXQ_STATE_READY, &mvmtxq->state);
+		mvmtxq->txq_id = IWL_MVM_INVALID_QUEUE;
+		spin_unlock_bh(&mvm->add_stream_lock);
 	}
 
 	/* Regardless if this is a reserved TXQ for a STA - mark it as false */
@@ -479,8 +482,11 @@ static int iwl_mvm_remove_sta_queue_marking(struct iwl_mvm *mvm, int queue)
 			disable_agg_tids |= BIT(tid);
 		mvmsta->tid_data[tid].txq_id = IWL_MVM_INVALID_QUEUE;
 
-		mvmtxq->txq_id = IWL_MVM_INVALID_QUEUE;
+		spin_lock_bh(&mvm->add_stream_lock);
 		list_del_init(&mvmtxq->list);
+		clear_bit(IWL_MVM_TXQ_STATE_READY, &mvmtxq->state);
+		mvmtxq->txq_id = IWL_MVM_INVALID_QUEUE;
+		spin_unlock_bh(&mvm->add_stream_lock);
 	}
 
 	mvmsta->tfd_queue_msk &= ~BIT(queue); /* Don't use this queue anymore */
@@ -693,7 +699,7 @@ static int iwl_mvm_redirect_queue(struct iwl_mvm *mvm, int queue, int tid,
 			    queue, iwl_mvm_ac_to_tx_fifo[ac]);
 
 	/* Stop the queue and wait for it to empty */
-	txq->stopped = true;
+	set_bit(IWL_MVM_TXQ_STATE_STOP_REDIRECT, &txq->state);
 
 	ret = iwl_trans_wait_tx_queues_empty(mvm->trans, BIT(queue));
 	if (ret) {
@@ -736,7 +742,7 @@ static int iwl_mvm_redirect_queue(struct iwl_mvm *mvm, int queue, int tid,
 
 out:
 	/* Continue using the queue */
-	txq->stopped = false;
+	clear_bit(IWL_MVM_TXQ_STATE_STOP_REDIRECT, &txq->state);
 
 	return ret;
 }
@@ -1444,12 +1450,22 @@ void iwl_mvm_add_new_dqa_stream_wk(struct work_struct *wk)
 		 * a queue in the function itself.
 		 */
 		if (iwl_mvm_sta_alloc_queue(mvm, txq->sta, txq->ac, tid)) {
+			spin_lock_bh(&mvm->add_stream_lock);
 			list_del_init(&mvmtxq->list);
+			spin_unlock_bh(&mvm->add_stream_lock);
 			continue;
 		}
 
-		list_del_init(&mvmtxq->list);
+		/* now we're ready, any remaining races/concurrency will be
+		 * handled in iwl_mvm_mac_itxq_xmit()
+		 */
+		set_bit(IWL_MVM_TXQ_STATE_READY, &mvmtxq->state);
+
 		local_bh_disable();
+		spin_lock(&mvm->add_stream_lock);
+		list_del_init(&mvmtxq->list);
+		spin_unlock(&mvm->add_stream_lock);
+
 		iwl_mvm_mac_itxq_xmit(mvm->hw, txq);
 		local_bh_enable();
 	}
@@ -1864,8 +1880,11 @@ static void iwl_mvm_disable_sta_queues(struct iwl_mvm *mvm,
 		struct iwl_mvm_txq *mvmtxq =
 			iwl_mvm_txq_from_mac80211(sta->txq[i]);
 
+		spin_lock_bh(&mvm->add_stream_lock);
 		mvmtxq->txq_id = IWL_MVM_INVALID_QUEUE;
 		list_del_init(&mvmtxq->list);
+		clear_bit(IWL_MVM_TXQ_STATE_READY, &mvmtxq->state);
+		spin_unlock_bh(&mvm->add_stream_lock);
 	}
 }