iwlwifi: mvm: ignore BAID for SN smaller than SSN

When we get SN that is smaller than SSN of the aggregation,
we shouldn't apply any reordering on them.
Further more, HW NSSN will be zeroed, which can cause us
to make some invalid decisions.
Detect the situation and invalidate the BAID.

Fixes: b915c101 ("iwlwifi: mvm: add reorder buffer per queue")
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -626,6 +626,7 @@ struct iwl_mvm_shared_mem_cfg {
  * @reorder_timer: timer for frames are in the reorder buffer. For AMSDU
  *	it is the time of last received sub-frame
  * @removed: prevent timer re-arming
+ * @valid: reordering is valid for this queue
  * @lock: protect reorder buffer internal state
  * @mvm: mvm pointer, needed for frame timer context
  */
@@ -641,6 +642,7 @@ struct iwl_mvm_reorder_buffer {
 	unsigned long reorder_time[IEEE80211_MAX_AMPDU_BUF];
 	struct timer_list reorder_timer;
 	bool removed;
+	bool valid;
 	spinlock_t lock;
 	struct iwl_mvm *mvm;
 } ____cacheline_aligned_in_smp;

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

@@ -636,9 +636,13 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 		return false;
 
 	baid_data = rcu_dereference(mvm->baid_map[baid]);
-	if (WARN(!baid_data,
-		 "Received baid %d, but no data exists for this BAID\n", baid))
+	if (!baid_data) {
+		WARN(!(reorder & IWL_RX_MPDU_REORDER_BA_OLD_SN),
+		     "Received baid %d, but no data exists for this BAID\n",
+		     baid);
 		return false;
+	}
+
 	if (WARN(tid != baid_data->tid || mvm_sta->sta_id != baid_data->sta_id,
 		 "baid 0x%x is mapped to sta:%d tid:%d, but was received for sta:%d tid:%d\n",
 		 baid, baid_data->sta_id, baid_data->tid, mvm_sta->sta_id,
@@ -653,6 +657,14 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 
 	spin_lock_bh(&buffer->lock);
 
+	if (!buffer->valid) {
+		if (reorder & IWL_RX_MPDU_REORDER_BA_OLD_SN) {
+			spin_unlock_bh(&buffer->lock);
+			return false;
+		}
+		buffer->valid = true;
+	}
+
 	if (ieee80211_is_back_req(hdr->frame_control)) {
 		iwl_mvm_release_frames(mvm, sta, napi, buffer, nssn);
 		goto drop;
@@ -737,7 +749,8 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 	return true;
 }
 
-static void iwl_mvm_agg_rx_received(struct iwl_mvm *mvm, u8 baid)
+static void iwl_mvm_agg_rx_received(struct iwl_mvm *mvm,
+				    u32 reorder_data, u8 baid)
 {
 	unsigned long now = jiffies;
 	unsigned long timeout;
@@ -746,8 +759,10 @@ static void iwl_mvm_agg_rx_received(struct iwl_mvm *mvm, u8 baid)
 	rcu_read_lock();
 
 	data = rcu_dereference(mvm->baid_map[baid]);
-	if (WARN_ON(!data))
+	if (!data) {
+		WARN_ON(!(reorder_data & IWL_RX_MPDU_REORDER_BA_OLD_SN));
 		goto out;
+	}
 
 	if (!data->timeout)
 		goto out;
@@ -925,8 +940,11 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 				mac_addr[i] = hdr->addr3[ETH_ALEN - i - 1];
 			ether_addr_copy(hdr->addr3, mac_addr);
 		}
-		if (baid != IWL_RX_REORDER_DATA_INVALID_BAID)
-			iwl_mvm_agg_rx_received(mvm, baid);
+		if (baid != IWL_RX_REORDER_DATA_INVALID_BAID) {
+			u32 reorder_data = le32_to_cpu(desc->reorder_data);
+
+			iwl_mvm_agg_rx_received(mvm, reorder_data, baid);
+		}
 	}
 
 	/* Set up the HT phy flags */

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

@@ -2231,6 +2231,7 @@ static void iwl_mvm_init_reorder_buffer(struct iwl_mvm *mvm,
 		reorder_buf->mvm = mvm;
 		reorder_buf->queue = i;
 		reorder_buf->sta_id = sta_id;
+		reorder_buf->valid = false;
 		for (j = 0; j < reorder_buf->buf_size; j++)
 			__skb_queue_head_init(&reorder_buf->entries[j]);
 	}