Fix iwm(4) performance drop after roaming between APs in 11n mode.

Stop BA sessions directly in iwm_run_stop() and disable Tx agg queues
when leaving RUN state. Otherwise Tx agg queues do not work properly
after switching APs and Tx performance drops to about 2 Mbit/s with
excessive retries being reported to RA.

Tested:
7260: florian
8260: bket
8265: stsp
9260: florian
9560: stsp

diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index 8bf1224..31e60bb 100644 (file)
--- a/sys/dev/pci/if_iwm.c
+++ b/sys/dev/pci/if_iwm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_iwm.c,v 1.370 2021/10/02 07:47:54 stsp Exp $       */
+/*     $OpenBSD: if_iwm.c,v 1.371 2021/10/05 10:34:36 stsp Exp $       */
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -307,6 +307,7 @@ int iwm_nic_init(struct iwm_softc *);
 int    iwm_enable_ac_txq(struct iwm_softc *, int, int);
 int    iwm_enable_txq(struct iwm_softc *, int, int, int, int, uint8_t,
            uint16_t);
+int    iwm_disable_txq(struct iwm_softc *, int, int, uint8_t);
 int    iwm_post_alive(struct iwm_softc *);
 struct iwm_phy_db_entry *iwm_phy_db_get_section(struct iwm_softc *, uint16_t,
            uint16_t);
@@ -2461,6 +2462,26 @@ iwm_enable_txq(struct iwm_softc *sc, int sta_id, int qid, int fifo,
        return 0;
 }
 
+int
+iwm_disable_txq(struct iwm_softc *sc, int sta_id, int qid, uint8_t tid)
+{
+       struct iwm_scd_txq_cfg_cmd cmd;
+       int err;
+
+       memset(&cmd, 0, sizeof(cmd));
+       cmd.tid = tid;
+       cmd.scd_queue = qid;
+       cmd.enable = 0;
+       cmd.sta_id = sta_id;
+
+       err = iwm_send_cmd_pdu(sc, IWM_SCD_QUEUE_CFG, 0, sizeof(cmd), &cmd);
+       if (err)
+               return err;
+
+       sc->qenablemsk &= ~(1 << qid);
+       return 0;
+}
+
 int
 iwm_post_alive(struct iwm_softc *sc)
 {
@@ -3397,7 +3418,6 @@ iwm_sta_tx_agg(struct iwm_softc *sc, struct ieee80211_node *ni, uint8_t tid,
        struct iwm_node *in = (void *)ni;
        int qid = IWM_FIRST_AGG_TX_QUEUE + tid;
        struct iwm_tx_ring *ring;
-       struct ieee80211_tx_ba *ba;
        enum ieee80211_edca_ac ac;
        int fifo;
        uint32_t status;
@@ -3417,7 +3437,6 @@ iwm_sta_tx_agg(struct iwm_softc *sc, struct ieee80211_node *ni, uint8_t tid,
        }
 
        ring = &sc->txq[qid];
-       ba = &ni->ni_tx_ba[tid];
        ac = iwm_tid_to_ac[tid];
        fifo = iwm_ac_to_tx_fifo[ac];
 
@@ -3434,7 +3453,10 @@ iwm_sta_tx_agg(struct iwm_softc *sc, struct ieee80211_node *ni, uint8_t tid,
                in->tfd_queue_msk |= (1 << qid);
        } else {
                in->tid_disable_ampdu |= (1 << tid);
-               /* Queue remains enabled in the TFD queue mask. */
+               /*
+                * Queue remains enabled in the TFD queue mask
+                * until we leave RUN state.
+                */
                err = iwm_flush_sta(sc, in);
                if (err)
                        return err;
@@ -3503,8 +3525,7 @@ iwm_sta_tx_agg(struct iwm_softc *sc, struct ieee80211_node *ni, uint8_t tid,
                 * Clear pending frames but keep the queue enabled.
                 * Firmware panics if we disable the queue here.
                 */
-               iwm_txq_advance(sc, ring,
-                   IWM_AGG_SSN_TO_TXQ_IDX(ba->ba_winend));
+               iwm_txq_advance(sc, ring, ring->cur);
                iwm_clear_oactive(sc, ring);
        }
 
@@ -3520,6 +3541,13 @@ iwm_ba_task(void *arg)
        int s = splnet();
        int tid, err = 0;
 
+       if ((sc->sc_flags & IWM_FLAG_SHUTDOWN) ||
+           ic->ic_state != IEEE80211_S_RUN) {
+               refcnt_rele_wake(&sc->task_refs);
+               splx(s);
+               return;
+       }
+
        for (tid = 0; tid < IWM_MAX_TID_COUNT && !err; tid++) {
                if (sc->sc_flags & IWM_FLAG_SHUTDOWN)
                        break;
@@ -8502,10 +8530,45 @@ iwm_run_stop(struct iwm_softc *sc)
 {
        struct ieee80211com *ic = &sc->sc_ic;
        struct iwm_node *in = (void *)ic->ic_bss;
-       int err;
+       struct ieee80211_node *ni = &in->in_ni;
+       int err, i, tid;
 
        splassert(IPL_NET);
 
+       /*
+        * Stop Tx/Rx BA sessions now. We cannot rely on the BA task
+        * for this when moving out of RUN state since it runs in a
+        * separate thread.
+        * Note that in->in_ni (struct ieee80211_node) already represents
+        * our new access point in case we are roaming between APs.
+        * This means we cannot rely on struct ieee802111_node to tell
+        * us which BA sessions exist.
+        */
+       for (i = 0; i < nitems(sc->sc_rxba_data); i++) {
+               struct iwm_rxba_data *rxba = &sc->sc_rxba_data[i];
+               if (rxba->baid == IWM_RX_REORDER_DATA_INVALID_BAID)
+                       continue;
+               err = iwm_sta_rx_agg(sc, ni, rxba->tid, 0, 0, 0, 0);
+               if (err)
+                       return err;
+               iwm_clear_reorder_buffer(sc, rxba);
+               if (sc->sc_rx_ba_sessions > 0)
+                       sc->sc_rx_ba_sessions--;
+       }
+       for (tid = 0; tid < IWM_MAX_TID_COUNT; tid++) {
+               int qid = IWM_FIRST_AGG_TX_QUEUE + tid;
+               if ((sc->tx_ba_queue_mask & (1 << qid)) == 0)
+                       continue;
+               err = iwm_sta_tx_agg(sc, ni, tid, 0, 0, 0);
+               if (err)
+                       return err;
+               err = iwm_disable_txq(sc, IWM_STATION_ID, qid, tid);
+               if (err)
+                       return err;
+               in->tfd_queue_msk &= ~(1 << qid);
+       }
+       ieee80211_ba_del(ni);
+
        if (ic->ic_opmode == IEEE80211_M_MONITOR)
                iwm_led_blink_stop(sc);
 
@@ -8940,7 +9003,6 @@ iwm_newstate(struct ieee80211com *ic, enum ieee80211_state nstate, int arg)
 {
        struct ifnet *ifp = IC2IFP(ic);
        struct iwm_softc *sc = ifp->if_softc;
-       int i;
 
        /*
         * Prevent attemps to transition towards the same state, unless
@@ -8954,10 +9016,6 @@ iwm_newstate(struct ieee80211com *ic, enum ieee80211_state nstate, int arg)
                timeout_del(&sc->sc_calib_to);
                iwm_del_task(sc, systq, &sc->ba_task);
                iwm_del_task(sc, systq, &sc->mac_ctxt_task);
-               for (i = 0; i < nitems(sc->sc_rxba_data); i++) {
-                       struct iwm_rxba_data *rxba = &sc->sc_rxba_data[i];
-                       iwm_clear_reorder_buffer(sc, rxba);
-               }
        }
 
        sc->ns_nstate = nstate;