iwlwifi: mvm: free AGG queue when we STA is removed

When we stop an AGG session, we need to look at the sequence
numbers in in the private area of the ieee80211_sta struct.
This allows us to know is the queue is empty. To get access
to this private area, we use fw_id_to_mac_id that maps
sta_id (index of the STA in fw table) to ieee80211_sta.

When the STA exists in fw, but not in mac80211, we set
an ERR ptr in fw_id_to_mac_id.

But if we first set an ERR ptr to fw_id_to_mac_id, and only
then flush the queues, then we won't be able to access the
sequence numbers in ieee80211_sta from the reclaim flow.
This means that we will never be able to release an AGG
queue when a station is deleted.

So first, flush the queue. That will let the reclaim flow
call iwl_mvm_check_ratid_empty which will disable the AGG
queue as needed, and only then, remove the mapping in
fw_id_to_mac_id.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/mvm/sta.c

@@ -340,6 +340,9 @@ int iwl_mvm_rm_sta(struct iwl_mvm *mvm,
 
 	if (vif->type == NL80211_IFTYPE_STATION &&
 	    mvmvif->ap_sta_id == mvm_sta->sta_id) {
+		/* flush its queues here since we are freeing mvm_sta */
+		ret = iwl_mvm_flush_tx_path(mvm, mvm_sta->tfd_queue_msk, true);
+
 		/*
 		 * Put a non-NULL since the fw station isn't removed.
 		 * It will be removed after the MAC will be set as
@@ -348,9 +351,6 @@ int iwl_mvm_rm_sta(struct iwl_mvm *mvm,
 		rcu_assign_pointer(mvm->fw_id_to_mac_id[mvm_sta->sta_id],
 				   ERR_PTR(-EINVAL));
 
-		/* flush its queues here since we are freeing mvm_sta */
-		ret = iwl_mvm_flush_tx_path(mvm, mvm_sta->tfd_queue_msk, true);
-
 		/* if we are associated - we can't remove the AP STA now */
 		if (vif->bss_conf.assoc)
 			return ret;