iwlwifi: mvm: add reorder buffer per queue

Next hardware will direct packets to core based on the TCP/UDP
streams.
This logic can create holes in reorder buffer since packets that
belong to other stream were directed to a different core.
However, those are valid holes and the packets can be indicated
in L3 order.

The hardware will utilize a mechanism of informing the driver of
the normalized ssn and the driver shall release all packets that
SN is lower than the nssn.
This enables managing the reorder across the queues without sharing
any data between them.

The reorder buffer is allocated and released directly in the RX path
in order to avoid various races between control path and rx path.
The code utilizes the internal messaging to notify rx queues of when
to delete the reorder buffer.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

1 files changed, 180 insertions, 1 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index 8d5717be6ab5..4f320dc478b6 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
@@ -395,6 +395,67 @@ int iwl_mvm_notify_rx_queue(struct iwl_mvm *mvm, u32 rxq_mask,
 	return ret;
 }
 
+static void iwl_mvm_release_frames(struct iwl_mvm *mvm,
+				   struct ieee80211_sta *sta,
+				   struct napi_struct *napi,
+				   struct iwl_mvm_reorder_buffer *reorder_buf,
+				   u16 nssn)
+{
+	u16 ssn = reorder_buf->head_sn;
+
+	while (ieee80211_sn_less(ssn, nssn)) {
+		int index = ssn % reorder_buf->buf_size;
+		struct sk_buff_head *skb_list = &reorder_buf->entries[index];
+		struct sk_buff *skb;
+
+		ssn = ieee80211_sn_inc(ssn);
+
+		/* holes are valid since nssn indicates frames were received. */
+		if (skb_queue_empty(skb_list) || !skb_peek_tail(skb_list))
+			continue;
+		/* Empty the list. Will have more than one frame for A-MSDU */
+		while ((skb = __skb_dequeue(skb_list))) {
+			iwl_mvm_pass_packet_to_mac80211(mvm, napi, skb,
+							reorder_buf->queue,
+							sta);
+			reorder_buf->num_stored--;
+		}
+	}
+	reorder_buf->head_sn = nssn;
+}
+
+static void iwl_mvm_del_ba(struct iwl_mvm *mvm, int queue,
+			   struct iwl_mvm_delba_data *data)
+{
+	struct iwl_mvm_baid_data *ba_data;
+	struct ieee80211_sta *sta;
+	struct iwl_mvm_reorder_buffer *reorder_buf;
+	u8 baid = data->baid;
+
+	if (WARN_ON_ONCE(baid >= IWL_RX_REORDER_DATA_INVALID_BAID))
+		return;
+
+	rcu_read_lock();
+
+	ba_data = rcu_dereference(mvm->baid_map[baid]);
+	if (WARN_ON_ONCE(!ba_data))
+		goto out;
+
+	sta = rcu_dereference(mvm->fw_id_to_mac_id[ba_data->sta_id]);
+	if (WARN_ON_ONCE(IS_ERR_OR_NULL(sta)))
+		goto out;
+
+	reorder_buf = &ba_data->reorder_buf[queue];
+
+	/* release all frames that are in the reorder buffer to the stack */
+	iwl_mvm_release_frames(mvm, sta, NULL, reorder_buf,
+			       ieee80211_sn_add(reorder_buf->head_sn,
+						reorder_buf->buf_size));
+
+out:
+	rcu_read_unlock();
+}
+
 void iwl_mvm_rx_queue_notif(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 			    int queue)
 {
@@ -418,12 +479,129 @@ void iwl_mvm_rx_queue_notif(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 	case IWL_MVM_RXQ_EMPTY:
 		break;
 	case IWL_MVM_RXQ_NOTIF_DEL_BA:
+		iwl_mvm_del_ba(mvm, queue, (void *)internal_notif->data);
 		break;
 	default:
 		WARN_ONCE(1, "Invalid identifier %d", internal_notif->type);
 	}
 }
 
+/*
+ * Returns true if the MPDU was buffered\dropped, false if it should be passed
+ * to upper layer.
+ */
+static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
+			    struct napi_struct *napi,
+			    int queue,
+			    struct ieee80211_sta *sta,
+			    struct sk_buff *skb,
+			    struct iwl_rx_mpdu_desc *desc)
+{
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+	struct iwl_mvm_sta *mvm_sta = iwl_mvm_sta_from_mac80211(sta);
+	struct iwl_mvm_baid_data *baid_data;
+	struct iwl_mvm_reorder_buffer *buffer;
+	struct sk_buff *tail;
+	u32 reorder = le32_to_cpu(desc->reorder_data);
+	bool amsdu = desc->mac_flags2 & IWL_RX_MPDU_MFLG2_AMSDU;
+	u8 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
+	u8 sub_frame_idx = desc->amsdu_info &
+			   IWL_RX_MPDU_AMSDU_SUBFRAME_IDX_MASK;
+	int index;
+	u16 nssn, sn;
+	u8 baid;
+
+	baid = (reorder & IWL_RX_MPDU_REORDER_BAID_MASK) >>
+		IWL_RX_MPDU_REORDER_BAID_SHIFT;
+
+	if (baid == IWL_RX_REORDER_DATA_INVALID_BAID)
+		return false;
+
+	/* no sta yet */
+	if (WARN_ON(IS_ERR_OR_NULL(sta)))
+		return false;
+
+	/* not a data packet */
+	if (!ieee80211_is_data_qos(hdr->frame_control) ||
+	    is_multicast_ether_addr(hdr->addr1))
+		return false;
+
+	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
+		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))
+		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,
+		 tid))
+		return false;
+
+	nssn = reorder & IWL_RX_MPDU_REORDER_NSSN_MASK;
+	sn = (reorder & IWL_RX_MPDU_REORDER_SN_MASK) >>
+		IWL_RX_MPDU_REORDER_SN_SHIFT;
+
+	buffer = &baid_data->reorder_buf[queue];
+
+	/*
+	 * If there was a significant jump in the nssn - adjust.
+	 * If the SN is smaller than the NSSN it might need to first go into
+	 * the reorder buffer, in which case we just release up to it and the
+	 * rest of the function will take of storing it and releasing up to the
+	 * nssn
+	 */
+	if (!ieee80211_sn_less(nssn, buffer->head_sn + buffer->buf_size)) {
+		u16 min_sn = ieee80211_sn_less(sn, nssn) ? sn : nssn;
+
+		iwl_mvm_release_frames(mvm, sta, napi, buffer, min_sn);
+	}
+
+	/* drop any oudated packets */
+	if (ieee80211_sn_less(sn, buffer->head_sn))
+		goto drop;
+
+	/* release immediately if allowed by nssn and no stored frames */
+	if (!buffer->num_stored && ieee80211_sn_less(sn, nssn)) {
+		buffer->head_sn = nssn;
+		/* No need to update AMSDU last SN - we are moving the head */
+		return false;
+	}
+
+	index = sn % buffer->buf_size;
+
+	/*
+	 * Check if we already stored this frame
+	 * As AMSDU is either received or not as whole, logic is simple:
+	 * If we have frames in that position in the buffer and the last frame
+	 * originated from AMSDU had a different SN then it is a retransmission.
+	 * If it is the same SN then if the subframe index is incrementing it
+	 * is the same AMSDU - otherwise it is a retransmission.
+	 */
+	tail = skb_peek_tail(&buffer->entries[index]);
+	if (tail && !amsdu)
+		goto drop;
+	else if (tail && (sn != buffer->last_amsdu ||
+			  buffer->last_sub_index >= sub_frame_idx))
+		goto drop;
+
+	/* put in reorder buffer */
+	__skb_queue_tail(&buffer->entries[index], skb);
+	buffer->num_stored++;
+	if (amsdu) {
+		buffer->last_amsdu = sn;
+		buffer->last_sub_index = sub_frame_idx;
+	}
+
+	iwl_mvm_release_frames(mvm, sta, napi, buffer, nssn);
+	return true;
+
+drop:
+	kfree_skb(skb);
+	return true;
+}
+
 static void iwl_mvm_agg_rx_received(struct iwl_mvm *mvm, u8 baid)
 {
 	unsigned long now = jiffies;
@@ -638,7 +816,8 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 	/* TODO: PHY info - gscan */
 
 	iwl_mvm_create_skb(skb, hdr, len, crypt_len, rxb);
-	iwl_mvm_pass_packet_to_mac80211(mvm, napi, skb, queue, sta);
+	if (!iwl_mvm_reorder(mvm, napi, queue, sta, skb, desc))
+		iwl_mvm_pass_packet_to_mac80211(mvm, napi, skb, queue, sta);
 	rcu_read_unlock();
 }