iwlwifi: mvm: support bss dynamic alloc/dealloc of queues

"DQA" is shorthand for "dynamic queue allocation". This
enables on-demand allocation of queues per RA/TID rather than
statically allocating per vif, thus allowing a potential
benefit of various factors.

Please refer to the DOC section this patch adds to sta.h to
see a more in-depth explanation of this feature.

There are many things to take into consideration when working
in DQA mode, and this patch is only one in a series. Note that
default operation mode is non-DQA mode, unless the FW
indicates that it supports DQA mode.

This patch enables support of DQA for a station connected to
an AP, and works in a non-aggregated mode.

When a frame for an unused RA/TID arrives at the driver, it
isn't TXed immediately, but deferred first until a suitable
queue is first allocated for it, and then TXed by a worker
that both allocates the queues and TXes deferred traffic.

When a STA is removed, its queues goes back into the queue
pools for reuse as needed.

Signed-off-by: Liad Kaufman <[email protected]>
Signed-off-by: Emmanuel Grumbach <[email protected]>

Author: lkaufman-he

drivers/net/wireless/intel/iwlwifi/mvm/d3.c

@@ -723,7 +723,7 @@ static int iwl_mvm_d3_reprogram(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 		return -EIO;
 	}
 
-	ret = iwl_mvm_sta_send_to_fw(mvm, ap_sta, false);
+	ret = iwl_mvm_sta_send_to_fw(mvm, ap_sta, false, 0);
 	if (ret)
 		return ret;
 	rcu_assign_pointer(mvm->fw_id_to_mac_id[mvmvif->ap_sta_id], ap_sta);

drivers/net/wireless/intel/iwlwifi/mvm/fw-api.h

@@ -80,12 +80,32 @@
 #include "fw-api-stats.h"
 #include "fw-api-tof.h"
 
-/* Tx queue numbers */
+/* Tx queue numbers for non-DQA mode */
 enum {
 	IWL_MVM_OFFCHANNEL_QUEUE = 8,
 	IWL_MVM_CMD_QUEUE = 9,
 };
 
+/*
+ * DQA queue numbers
+ *
+ * @IWL_MVM_DQA_MIN_MGMT_QUEUE: first TXQ in pool for MGMT and non-QOS frames.
+ *	Each MGMT queue is mapped to a single STA
+ *	MGMT frames are frames that return true on ieee80211_is_mgmt()
+ * @IWL_MVM_DQA_MAX_MGMT_QUEUE: last TXQ in pool for MGMT frames
+ * @IWL_MVM_DQA_MIN_DATA_QUEUE: first TXQ in pool for DATA frames.
+ *	DATA frames are intended for !ieee80211_is_mgmt() frames, but if
+ *	the MGMT TXQ pool is exhausted, mgmt frames can be sent on DATA queues
+ *	as well
+ * @IWL_MVM_DQA_MAX_DATA_QUEUE: last TXQ in pool for DATA frames
+ */
+enum iwl_mvm_dqa_txq {
+	IWL_MVM_DQA_MIN_MGMT_QUEUE = 5,
+	IWL_MVM_DQA_MAX_MGMT_QUEUE = 8,
+	IWL_MVM_DQA_MIN_DATA_QUEUE = 10,
+	IWL_MVM_DQA_MAX_DATA_QUEUE = 31,
+};
+
 enum iwl_mvm_tx_fifo {
 	IWL_MVM_TX_FIFO_BK = 0,
 	IWL_MVM_TX_FIFO_BE,

drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c

@@ -425,12 +425,17 @@ static int iwl_mvm_mac_ctxt_allocate_resources(struct iwl_mvm *mvm,
 		return 0;
 	}
 
-	/* Find available queues, and allocate them to the ACs */
+	/*
+	 * Find available queues, and allocate them to the ACs. When in
+	 * DQA-mode they aren't really used, and this is done only so the
+	 * mac80211 ieee80211_check_queues() function won't fail
+	 */
 	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
 		u8 queue = find_first_zero_bit(&used_hw_queues,
 					       mvm->first_agg_queue);
 
-		if (queue >= mvm->first_agg_queue) {
+		if (!iwl_mvm_is_dqa_supported(mvm) &&
+		    queue >= mvm->first_agg_queue) {
 			IWL_ERR(mvm, "Failed to allocate queue\n");
 			ret = -EIO;
 			goto exit_fail;
@@ -495,6 +500,10 @@ int iwl_mvm_mac_ctxt_init(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
 				      IWL_MVM_TX_FIFO_MCAST, 0, wdg_timeout);
 		/* fall through */
 	default:
+		/* If DQA is supported - queues will be enabled when needed */
+		if (iwl_mvm_is_dqa_supported(mvm))
+			break;
+
 		for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
 			iwl_mvm_enable_ac_txq(mvm, vif->hw_queue[ac],
 					      vif->hw_queue[ac],
@@ -523,6 +532,14 @@ void iwl_mvm_mac_ctxt_release(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
 				    IWL_MAX_TID_COUNT, 0);
 		/* fall through */
 	default:
+		/*
+		 * If DQA is supported - queues were already disabled, since in
+		 * DQA-mode the queues are a property of the STA and not of the
+		 * vif, and at this point the STA was already deleted
+		 */
+		if (iwl_mvm_is_dqa_supported(mvm))
+			break;
+
 		for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
 			iwl_mvm_disable_txq(mvm, vif->hw_queue[ac],
 					    vif->hw_queue[ac],

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

@@ -992,6 +992,7 @@ static void iwl_mvm_restart_cleanup(struct iwl_mvm *mvm)
 	iwl_mvm_reset_phy_ctxts(mvm);
 	memset(mvm->fw_key_table, 0, sizeof(mvm->fw_key_table));
 	memset(mvm->sta_drained, 0, sizeof(mvm->sta_drained));
+	memset(mvm->sta_deferred_frames, 0, sizeof(mvm->sta_deferred_frames));
 	memset(mvm->tfd_drained, 0, sizeof(mvm->tfd_drained));
 	memset(&mvm->last_bt_notif, 0, sizeof(mvm->last_bt_notif));
 	memset(&mvm->last_bt_notif_old, 0, sizeof(mvm->last_bt_notif_old));
@@ -1178,6 +1179,7 @@ static void iwl_mvm_mac_stop(struct ieee80211_hw *hw)
 
 	flush_work(&mvm->d0i3_exit_work);
 	flush_work(&mvm->async_handlers_wk);
+	flush_work(&mvm->add_stream_wk);
 	cancel_delayed_work_sync(&mvm->fw_dump_wk);
 	iwl_mvm_free_fw_dump_desc(mvm);
 
@@ -2382,6 +2384,22 @@ iwl_mvm_tdls_check_trigger(struct iwl_mvm *mvm,
 				    peer_addr, action);
 }
 
+static void iwl_mvm_purge_deferred_tx_frames(struct iwl_mvm *mvm,
+					     struct iwl_mvm_sta *mvm_sta)
+{
+	struct iwl_mvm_tid_data *tid_data;
+	struct sk_buff *skb;
+	int i;
+
+	spin_lock_bh(&mvm_sta->lock);
+	for (i = 0; i <= IWL_MAX_TID_COUNT; i++) {
+		tid_data = &mvm_sta->tid_data[i];
+		while ((skb = __skb_dequeue(&tid_data->deferred_tx_frames)))
+			ieee80211_free_txskb(mvm->hw, skb);
+	}
+	spin_unlock_bh(&mvm_sta->lock);
+}
+
 static int iwl_mvm_mac_sta_state(struct ieee80211_hw *hw,
 				 struct ieee80211_vif *vif,
 				 struct ieee80211_sta *sta,
@@ -2402,6 +2420,33 @@ static int iwl_mvm_mac_sta_state(struct ieee80211_hw *hw,
 	/* if a STA is being removed, reuse its ID */
 	flush_work(&mvm->sta_drained_wk);
 
+	/*
+	 * If we are in a STA removal flow and in DQA mode:
+	 *
+	 * This is after the sync_rcu part, so the queues have already been
+	 * flushed. No more TXs on their way in mac80211's path, and no more in
+	 * the queues.
+	 * Also, we won't be getting any new TX frames for this station.
+	 * What we might have are deferred TX frames that need to be taken care
+	 * of.
+	 *
+	 * Drop any still-queued deferred-frame before removing the STA, and
+	 * make sure the worker is no longer handling frames for this STA.
+	 */
+	if (old_state == IEEE80211_STA_NONE &&
+	    new_state == IEEE80211_STA_NOTEXIST &&
+	    iwl_mvm_is_dqa_supported(mvm)) {
+		struct iwl_mvm_sta *mvm_sta = iwl_mvm_sta_from_mac80211(sta);
+
+		iwl_mvm_purge_deferred_tx_frames(mvm, mvm_sta);
+		flush_work(&mvm->add_stream_wk);
+
+		/*
+		 * No need to make sure deferred TX indication is off since the
+		 * worker will already remove it if it was on
+		 */
+	}
+
 	mutex_lock(&mvm->mutex);
 	if (old_state == IEEE80211_STA_NOTEXIST &&
 	    new_state == IEEE80211_STA_NONE) {
@@ -3738,6 +3783,10 @@ static void iwl_mvm_mac_flush(struct ieee80211_hw *hw,
 	if (!vif || vif->type != NL80211_IFTYPE_STATION)
 		return;
 
+	/* Make sure we're done with the deferred traffic before flushing */
+	if (iwl_mvm_is_dqa_supported(mvm))
+		flush_work(&mvm->add_stream_wk);
+
 	mutex_lock(&mvm->mutex);
 	mvmvif = iwl_mvm_vif_from_mac80211(vif);
 

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -665,10 +665,16 @@ struct iwl_mvm {
 		/* Map to HW queue */
 		u32 hw_queue_to_mac80211;
 		u8 hw_queue_refcount;
+		/*
+		 * This is to mark that queue is reserved for a STA but not yet
+		 * allocated. This is needed to make sure we have at least one
+		 * available queue to use when adding a new STA
+		 */
 		bool setup_reserved;
 		u16 tid_bitmap; /* Bitmap of the TIDs mapped to this queue */
 	} queue_info[IWL_MAX_HW_QUEUES];
 	spinlock_t queue_info_lock; /* For syncing queue mgmt operations */
+	struct work_struct add_stream_wk; /* To add streams to queues */
 	atomic_t mac80211_queue_stop_count[IEEE80211_MAX_QUEUES];
 
 	const char *nvm_file_name;
@@ -688,6 +694,7 @@ struct iwl_mvm {
 	struct iwl_rx_phy_info last_phy_info;
 	struct ieee80211_sta __rcu *fw_id_to_mac_id[IWL_MVM_STATION_COUNT];
 	struct work_struct sta_drained_wk;
+	unsigned long sta_deferred_frames[BITS_TO_LONGS(IWL_MVM_STATION_COUNT)];
 	unsigned long sta_drained[BITS_TO_LONGS(IWL_MVM_STATION_COUNT)];
 	atomic_t pending_frames[IWL_MVM_STATION_COUNT];
 	u32 tfd_drained[IWL_MVM_STATION_COUNT];

drivers/net/wireless/intel/iwlwifi/mvm/ops.c

@@ -579,6 +579,7 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 	INIT_WORK(&mvm->d0i3_exit_work, iwl_mvm_d0i3_exit_work);
 	INIT_DELAYED_WORK(&mvm->fw_dump_wk, iwl_mvm_fw_error_dump_wk);
 	INIT_DELAYED_WORK(&mvm->tdls_cs.dwork, iwl_mvm_tdls_ch_switch_work);
+	INIT_WORK(&mvm->add_stream_wk, iwl_mvm_add_new_dqa_stream_wk);
 
 	spin_lock_init(&mvm->d0i3_tx_lock);
 	spin_lock_init(&mvm->refs_lock);