Commit ecd09ddc authored by Emmanuel Grumbach's avatar Emmanuel Grumbach Committed by Johannes Berg
Browse files

iwlwifi: mvm: fix frame drop from the reordering buffer 



An earlier patch made sure that the queues are not lagging
too far behind. This means that iwl_mvm_release_frames
should not be called with a head_sn too far behind NSSN.

Don't take the risk to change completely the entry
condition to iwl_mvm_release_frames, but don't update
the head_sn is the NSSN is more than 2048 packets ahead
of us. Since this just cannot be right. This means that
the scenario described here happened. We are queue 0.

	Q:0				Q:1
	head_sn: 0    -> 2047
					head_sn: 2048

	Lots of packets arrive:
	head_sn: 2047 -> 2150

					send NSSN_SYNC notification

	Handle notification
	from the firmware and
	do NOT move the head_sn
	back to 2048

Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: default avatarLuca Coelho <luciano.coelho@intel.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent f5d88fa3

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

+33 −11
Original line number Diff line number Diff line
@@ -518,12 +518,17 @@ static void iwl_mvm_sync_nssn(struct iwl_mvm *mvm, u8 baid, u16 nssn) 


#define RX_REORDER_BUF_TIMEOUT_MQ (HZ / 10)



enum iwl_mvm_release_flags {

	IWL_MVM_RELEASE_SEND_RSS_SYNC = BIT(0),

	IWL_MVM_RELEASE_FROM_RSS_SYNC = BIT(1),

};



static void iwl_mvm_release_frames(struct iwl_mvm *mvm,

				   struct ieee80211_sta *sta,

				   struct napi_struct *napi,

				   struct iwl_mvm_baid_data *baid_data,

				   struct iwl_mvm_reorder_buffer *reorder_buf,

				   u16 nssn, bool sync_rss)

				   u16 nssn, u32 flags)

{

	struct iwl_mvm_reorder_buf_entry *entries =

		&baid_data->entries[reorder_buf->queue *
@@ -532,6 +537,18 @@ static void iwl_mvm_release_frames(struct iwl_mvm *mvm, 


	lockdep_assert_held(&reorder_buf->lock);



	/*

	 * We keep the NSSN not too far behind, if we are sync'ing it and it

	 * is more than 2048 ahead of us, it must be behind us. Discard it.

	 * This can happen if the queue that hit the 0 / 2048 seqno was lagging

	 * behind and this queue already processed packets. The next if

	 * would have caught cases where this queue would have processed less

	 * than 64 packets, but it may have processed more than 64 packets.

	 */

	if ((flags & IWL_MVM_RELEASE_FROM_RSS_SYNC) &&

	    ieee80211_sn_less(nssn, ssn))

		goto set_timer;



	/* ignore nssn smaller than head sn - this can happen due to timeout */

	if (iwl_mvm_is_sn_less(nssn, ssn, reorder_buf->buf_size))

		goto set_timer;
@@ -542,7 +559,8 @@ static void iwl_mvm_release_frames(struct iwl_mvm *mvm, 
		struct sk_buff *skb;



		ssn = ieee80211_sn_inc(ssn);

		if (sync_rss && (ssn == 2048 || ssn == 0))

		if ((flags & IWL_MVM_RELEASE_SEND_RSS_SYNC) &&

		    (ssn == 2048 || ssn == 0))

			iwl_mvm_sync_nssn(mvm, baid_data->baid, ssn);



		/*
@@ -631,7 +649,7 @@ void iwl_mvm_reorder_timer_expired(struct timer_list *t) 
		iwl_mvm_event_frame_timeout_callback(buf->mvm, mvmsta->vif,

						     sta, baid_data->tid);

		iwl_mvm_release_frames(buf->mvm, sta, NULL, baid_data,

				       buf, sn, true);

				       buf, sn, IWL_MVM_RELEASE_SEND_RSS_SYNC);

		rcu_read_unlock();

	} else {

		/*
@@ -674,7 +692,7 @@ static void iwl_mvm_del_ba(struct iwl_mvm *mvm, int queue, 
	iwl_mvm_release_frames(mvm, sta, NULL, ba_data, reorder_buf,

			       ieee80211_sn_add(reorder_buf->head_sn,

						reorder_buf->buf_size),

			       false);

			       0);

	spin_unlock_bh(&reorder_buf->lock);

	del_timer_sync(&reorder_buf->reorder_timer);
@@ -684,7 +702,8 @@ out: 


static void iwl_mvm_release_frames_from_notif(struct iwl_mvm *mvm,

					      struct napi_struct *napi,

					      u8 baid, u16 nssn, int queue)

					      u8 baid, u16 nssn, int queue,

					      u32 flags)

{

	struct ieee80211_sta *sta;

	struct iwl_mvm_reorder_buffer *reorder_buf;
@@ -711,7 +730,7 @@ static void iwl_mvm_release_frames_from_notif(struct iwl_mvm *mvm, 


	spin_lock_bh(&reorder_buf->lock);

	iwl_mvm_release_frames(mvm, sta, napi, ba_data,

			       reorder_buf, nssn, false);

			       reorder_buf, nssn, flags);

	spin_unlock_bh(&reorder_buf->lock);



out:
@@ -723,7 +742,8 @@ static void iwl_mvm_nssn_sync(struct iwl_mvm *mvm, 
			      const struct iwl_mvm_nssn_sync_data *data)

{

	iwl_mvm_release_frames_from_notif(mvm, napi, data->baid,

					  data->nssn, queue);

					  data->nssn, queue,

					  IWL_MVM_RELEASE_FROM_RSS_SYNC);

}



void iwl_mvm_rx_queue_notif(struct iwl_mvm *mvm, struct napi_struct *napi,
@@ -851,7 +871,7 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm, 


	if (ieee80211_is_back_req(hdr->frame_control)) {

		iwl_mvm_release_frames(mvm, sta, napi, baid_data,

				       buffer, nssn, false);

				       buffer, nssn, 0);

		goto drop;

	}
@@ -871,7 +891,7 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm, 
		u16 min_sn = ieee80211_sn_less(sn, nssn) ? sn : nssn;



		iwl_mvm_release_frames(mvm, sta, napi, baid_data, buffer,

				       min_sn, true);

				       min_sn, IWL_MVM_RELEASE_SEND_RSS_SYNC);

	}



	/* drop any oudated packets */
@@ -963,7 +983,8 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm, 
	 */

	if (!amsdu || last_subframe)

		iwl_mvm_release_frames(mvm, sta, napi, baid_data,

				       buffer, nssn, true);

				       buffer, nssn,

				       IWL_MVM_RELEASE_SEND_RSS_SYNC);



	spin_unlock_bh(&buffer->lock);

	return true;
@@ -1936,5 +1957,6 @@ void iwl_mvm_rx_frame_release(struct iwl_mvm *mvm, struct napi_struct *napi, 
	struct iwl_frame_release *release = (void *)pkt->data;



	iwl_mvm_release_frames_from_notif(mvm, napi, release->baid,

					  le16_to_cpu(release->nssn), queue);

					  le16_to_cpu(release->nssn),

					  queue, 0);

}

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