iwlwifi: mvm: remove queue_info_lock

All the queue management code runs under mvm->mutex, so there are
only very few cases of accessing the data structures without it:
 * TX path, which doesn't take any locks anyway
 * iwl_mvm_wake_sw_queue() and iwl_mvm_stop_sw_queue() where we
   just (atomically) read a bitmap, so the lock isn't needed.

Therefore, we can remove the spinlock. This enables some cleanup
in the ugly locking in iwl_mvm_inactivity_check().
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -844,7 +844,6 @@ struct iwl_mvm {
 	u16 hw_queue_to_mac80211[IWL_MAX_TVQM_QUEUES];
 
 	struct iwl_mvm_dqa_txq_info 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];

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

@@ -676,7 +676,6 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 	INIT_LIST_HEAD(&mvm->aux_roc_te_list);
 	INIT_LIST_HEAD(&mvm->async_handlers_list);
 	spin_lock_init(&mvm->time_event_lock);
-	spin_lock_init(&mvm->queue_info_lock);
 
 	INIT_WORK(&mvm->async_handlers_wk, iwl_mvm_async_handlers_wk);
 	INIT_WORK(&mvm->roc_done_wk, iwl_mvm_roc_done_wk);
@@ -1108,11 +1107,7 @@ static void iwl_mvm_async_cb(struct iwl_op_mode *op_mode,
 static void iwl_mvm_stop_sw_queue(struct iwl_op_mode *op_mode, int hw_queue)
 {
 	struct iwl_mvm *mvm = IWL_OP_MODE_GET_MVM(op_mode);
-	unsigned long mq;
-
-	spin_lock_bh(&mvm->queue_info_lock);
-	mq = mvm->hw_queue_to_mac80211[hw_queue];
-	spin_unlock_bh(&mvm->queue_info_lock);
+	unsigned long mq = mvm->hw_queue_to_mac80211[hw_queue];
 
 	iwl_mvm_stop_mac_queues(mvm, mq);
 }
@@ -1138,11 +1133,7 @@ void iwl_mvm_start_mac_queues(struct iwl_mvm *mvm, unsigned long mq)
 static void iwl_mvm_wake_sw_queue(struct iwl_op_mode *op_mode, int hw_queue)
 {
 	struct iwl_mvm *mvm = IWL_OP_MODE_GET_MVM(op_mode);
-	unsigned long mq;
-
-	spin_lock_bh(&mvm->queue_info_lock);
-	mq = mvm->hw_queue_to_mac80211[hw_queue];
-	spin_unlock_bh(&mvm->queue_info_lock);
+	unsigned long mq = mvm->hw_queue_to_mac80211[hw_queue];
 
 	iwl_mvm_start_mac_queues(mvm, mq);
 }

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

@@ -1160,11 +1160,11 @@ static int iwl_mvm_tx_mpdu(struct iwl_mvm *mvm, struct sk_buff *skb,
 		 * If we have timed-out TIDs - schedule the worker that will
 		 * reconfig the queues and update them
 		 *
-		 * Note that the mvm->queue_info_lock isn't being taken here in
-		 * order to not serialize the TX flow. This isn't dangerous
-		 * because scheduling mvm->add_stream_wk can't ruin the state,
-		 * and if we DON'T schedule it due to some race condition then
-		 * next TX we get here we will.
+		 * Note that the no lock is taken here in order to not serialize
+		 * the TX flow. This isn't dangerous because scheduling
+		 * mvm->add_stream_wk can't ruin the state, and if we DON'T
+		 * schedule it due to some race condition then next TX we get
+		 * here we will.
 		 */
 		if (unlikely(mvm->queue_info[txq_id].status ==
 			     IWL_MVM_QUEUE_SHARED &&

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

@@ -618,13 +618,9 @@ int iwl_mvm_reconfig_scd(struct iwl_mvm *mvm, int queue, int fifo, int sta_id,
 	if (WARN_ON(iwl_mvm_has_new_tx_api(mvm)))
 		return -EINVAL;
 
-	spin_lock_bh(&mvm->queue_info_lock);
 	if (WARN(mvm->queue_info[queue].tid_bitmap == 0,
-		 "Trying to reconfig unallocated queue %d\n", queue)) {
-		spin_unlock_bh(&mvm->queue_info_lock);
+		 "Trying to reconfig unallocated queue %d\n", queue))
 		return -ENXIO;
-	}
-	spin_unlock_bh(&mvm->queue_info_lock);
 
 	IWL_DEBUG_TX_QUEUES(mvm, "Reconfig SCD for TXQ #%d\n", queue);