From ecd09ddc1d14cca4f874151aed51a7feee3f765b Mon Sep 17 00:00:00 2001 From: Emmanuel Grumbach Date: Thu, 27 Jun 2019 21:50:24 +0300 Subject: [PATCH] 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: Emmanuel Grumbach Signed-off-by: Luca Coelho Signed-off-by: Johannes Berg --- drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c | 44 ++++++++++++++++++++------- 1 file changed, 33 insertions(+), 11 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c index 4f4fdaf..854edd7 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c @@ -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); } -- 2.7.4