ath9k: Revamp TX aggregation

This patch cleans up the convoluted buffer management
logic for TX aggregation. Both aggregation creation and
completion are addressed.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 93 insertions, 212 deletions

diff --git a/drivers/net/wireless/ath9k/xmit.c b/drivers/net/wireless/ath9k/xmit.c
index d7cec0fee34c..0d05a7f8903f 100644
--- a/drivers/net/wireless/ath9k/xmit.c
+++ b/drivers/net/wireless/ath9k/xmit.c
@@ -151,7 +151,7 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
         while (!list_empty(&tid->buf_q)) {
                 bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
                 ASSERT(!bf_isretried(bf));
-                list_cut_position(&bf_head, &tid->buf_q, &bf->bf_lastfrm->list);
+                list_move_tail(&bf->list, &bf_head);
                 ath_tx_send_normal(sc, txq, tid, &bf_head);
         }
 
@@ -212,9 +212,9 @@ static void ath_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
         for (;;) {
                 if (list_empty(&tid->buf_q))
                         break;
-                bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
 
-                list_cut_position(&bf_head, &tid->buf_q, &bf->bf_lastfrm->list);
+                bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
+                list_move_tail(&bf->list, &bf_head);
 
                 if (bf_isretried(bf))
                         ath_tx_update_baw(sc, tid, bf->bf_seqno);
@@ -241,17 +241,37 @@ static void ath_tx_set_retry(struct ath_softc *sc, struct ath_buf *bf)
         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_RETRY);
 }
 
-static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
-                                      struct ath_buf *bf, struct list_head *bf_q,
-                                      int txok)
+static struct ath_buf* ath_clone_txbuf(struct ath_softc *sc, struct ath_buf *bf)
+{
+        struct ath_buf *tbf;
+
+        spin_lock_bh(&sc->tx.txbuflock);
+        ASSERT(!list_empty((&sc->tx.txbuf)));
+        tbf = list_first_entry(&sc->tx.txbuf, struct ath_buf, list);
+        list_del(&tbf->list);
+        spin_unlock_bh(&sc->tx.txbuflock);
+
+        ATH_TXBUF_RESET(tbf);
+
+        tbf->bf_mpdu = bf->bf_mpdu;
+        tbf->bf_buf_addr = bf->bf_buf_addr;
+        *(tbf->bf_desc) = *(bf->bf_desc);
+        tbf->bf_state = bf->bf_state;
+        tbf->bf_dmacontext = bf->bf_dmacontext;
+
+        return tbf;
+}
+
+static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
+                                 struct ath_buf *bf, struct list_head *bf_q,
+                                 int txok)
 {
         struct ath_node *an = NULL;
         struct sk_buff *skb;
         struct ieee80211_tx_info *tx_info;
         struct ath_atx_tid *tid = NULL;
-        struct ath_buf *bf_last = bf->bf_lastbf;
+        struct ath_buf *bf_next, *bf_last = bf->bf_lastbf;
         struct ath_desc *ds = bf_last->bf_desc;
-        struct ath_buf *bf_next, *bf_lastq = NULL;
         struct list_head bf_head, bf_pending;
         u16 seq_st = 0;
         u32 ba[WME_BA_BMP_SIZE >> 5];
@@ -266,28 +286,23 @@ static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
         }
 
         isaggr = bf_isaggr(bf);
-        if (isaggr) {
-                if (txok) {
-                        if (ATH_DS_TX_BA(ds)) {
-                                seq_st = ATH_DS_BA_SEQ(ds);
-                                memcpy(ba, ATH_DS_BA_BITMAP(ds),
-                                       WME_BA_BMP_SIZE >> 3);
-                        } else {
-                                memset(ba, 0, WME_BA_BMP_SIZE >> 3);
+        memset(ba, 0, WME_BA_BMP_SIZE >> 3);
 
-                                /*
-                                 * AR5416 can become deaf/mute when BA
-                                 * issue happens. Chip needs to be reset.
-                                 * But AP code may have sychronization issues
-                                 * when perform internal reset in this routine.
-                                 * Only enable reset in STA mode for now.
-                                 */
-                                if (sc->sc_ah->ah_opmode ==
-                                            NL80211_IFTYPE_STATION)
-                                        needreset = 1;
-                        }
+        if (isaggr && txok) {
+                if (ATH_DS_TX_BA(ds)) {
+                        seq_st = ATH_DS_BA_SEQ(ds);
+                        memcpy(ba, ATH_DS_BA_BITMAP(ds),
+                               WME_BA_BMP_SIZE >> 3);
                 } else {
-                        memset(ba, 0, WME_BA_BMP_SIZE >> 3);
+                        /*
+                         * AR5416 can become deaf/mute when BA
+                         * issue happens. Chip needs to be reset.
+                         * But AP code may have sychronization issues
+                         * when perform internal reset in this routine.
+                         * Only enable reset in STA mode for now.
+                         */
+                        if (sc->sc_ah->ah_opmode == NL80211_IFTYPE_STATION)
+                                needreset = 1;
                 }
         }
 
@@ -304,7 +319,6 @@ static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
                 } else if (!isaggr && txok) {
                         /* transmit completion */
                 } else {
-
                         if (!(tid->state & AGGR_CLEANUP) &&
                             ds->ds_txstat.ts_flags != ATH9K_TX_SW_ABORTED) {
                                 if (bf->bf_retries < ATH_MAX_SW_RETRIES) {
@@ -325,19 +339,10 @@ static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
                 }
 
                 if (bf_next == NULL) {
-                        ASSERT(bf->bf_lastfrm == bf_last);
-                        if (!list_empty(bf_q)) {
-                                bf_lastq = list_entry(bf_q->prev,
-                                        struct ath_buf, list);
-                                list_cut_position(&bf_head,
-                                        bf_q, &bf_lastq->list);
-                        } else {
-                                INIT_LIST_HEAD(&bf_head);
-                        }
+                        INIT_LIST_HEAD(&bf_head);
                 } else {
                         ASSERT(!list_empty(bf_q));
-                        list_cut_position(&bf_head,
-                                bf_q, &bf->bf_lastfrm->list);
+                        list_move_tail(&bf->list, &bf_head);
                 }
 
                 if (!txpending) {
@@ -351,53 +356,20 @@ static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
 
                         ath_tx_complete_buf(sc, bf, &bf_head, !txfail, sendbar);
                 } else {
-                        /*
-                         * retry the un-acked ones
-                         */
+                        /* retry the un-acked ones */
                         if (bf->bf_next == NULL &&
                             bf_last->bf_status & ATH_BUFSTATUS_STALE) {
                                 struct ath_buf *tbf;
 
-                                /* allocate new descriptor */
-                                spin_lock_bh(&sc->tx.txbuflock);
-                                ASSERT(!list_empty((&sc->tx.txbuf)));
-                                tbf = list_first_entry(&sc->tx.txbuf,
-                                                struct ath_buf, list);
-                                list_del(&tbf->list);
-                                spin_unlock_bh(&sc->tx.txbuflock);
-
-                                ATH_TXBUF_RESET(tbf);
-
-                                /* copy descriptor content */
-                                tbf->bf_mpdu = bf_last->bf_mpdu;
-                                tbf->bf_buf_addr = bf_last->bf_buf_addr;
-                                *(tbf->bf_desc) = *(bf_last->bf_desc);
-
-                                /* link it to the frame */
-                                if (bf_lastq) {
-                                        bf_lastq->bf_desc->ds_link =
-                                                tbf->bf_daddr;
-                                        bf->bf_lastfrm = tbf;
-                                        ath9k_hw_cleartxdesc(sc->sc_ah,
-                                                bf->bf_lastfrm->bf_desc);
-                                } else {
-                                        tbf->bf_state = bf_last->bf_state;
-                                        tbf->bf_lastfrm = tbf;
-                                        ath9k_hw_cleartxdesc(sc->sc_ah,
-                                                tbf->bf_lastfrm->bf_desc);
-
-                                        /* copy the DMA context */
-                                        tbf->bf_dmacontext =
-                                                bf_last->bf_dmacontext;
-                                }
+                                tbf = ath_clone_txbuf(sc, bf_last);
+                                ath9k_hw_cleartxdesc(sc->sc_ah, tbf->bf_desc);
                                 list_add_tail(&tbf->list, &bf_head);
                         } else {
                                 /*
                                  * Clear descriptor status words for
                                  * software retry
                                  */
-                                ath9k_hw_cleartxdesc(sc->sc_ah,
-                                                     bf->bf_lastfrm->bf_desc);
+                                ath9k_hw_cleartxdesc(sc->sc_ah, bf->bf_desc);
                         }
 
                         /*
@@ -411,27 +383,18 @@ static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
         }
 
         if (tid->state & AGGR_CLEANUP) {
-                /* check to see if we're done with cleaning the h/w queue */
-                spin_lock_bh(&txq->axq_lock);
-
                 if (tid->baw_head == tid->baw_tail) {
                         tid->state &= ~AGGR_ADDBA_COMPLETE;
                         tid->addba_exchangeattempts = 0;
-                        spin_unlock_bh(&txq->axq_lock);
-
                         tid->state &= ~AGGR_CLEANUP;
 
                         /* send buffered frames as singles */
                         ath_tx_flush_tid(sc, tid);
-                } else
-                        spin_unlock_bh(&txq->axq_lock);
-
+                }
                 return;
         }
 
-        /*
-         * prepend un-acked frames to the beginning of the pending frame queue
-         */
+        /* prepend un-acked frames to the beginning of the pending frame queue */
         if (!list_empty(&bf_pending)) {
                 spin_lock_bh(&txq->axq_lock);
                 list_splice(&bf_pending, &tid->buf_q);
@@ -441,8 +404,6 @@ static void ath_tx_complete_aggr_rifs(struct ath_softc *sc, struct ath_txq *txq,
 
         if (needreset)
                 ath_reset(sc, false);
-
-        return;
 }
 
 static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
@@ -453,15 +414,14 @@ static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
         struct ieee80211_tx_info *tx_info;
         struct ieee80211_tx_rate *rates;
         struct ath_tx_info_priv *tx_info_priv;
-        u32 max_4ms_framelen, frame_length;
+        u32 max_4ms_framelen, frmlen;
         u16 aggr_limit, legacy = 0, maxampdu;
         int i;
 
         skb = (struct sk_buff *)bf->bf_mpdu;
         tx_info = IEEE80211_SKB_CB(skb);
         rates = tx_info->control.rates;
-        tx_info_priv =
-                (struct ath_tx_info_priv *)tx_info->rate_driver_data[0];
+        tx_info_priv = (struct ath_tx_info_priv *)tx_info->rate_driver_data[0];
 
         /*
          * Find the lowest frame length among the rate series that will have a
@@ -477,9 +437,8 @@ static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
                                 break;
                         }
 
-                        frame_length =
-                                rate_table->info[rates[i].idx].max_4ms_framelen;
-                        max_4ms_framelen = min(max_4ms_framelen, frame_length);
+                        frmlen = rate_table->info[rates[i].idx].max_4ms_framelen;
+                        max_4ms_framelen = min(max_4ms_framelen, frmlen);
                 }
         }
 
@@ -491,8 +450,7 @@ static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
         if (tx_info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE || legacy)
                 return 0;
 
-        aggr_limit = min(max_4ms_framelen,
-                (u32)ATH_AMPDU_LIMIT_DEFAULT);
+        aggr_limit = min(max_4ms_framelen, (u32)ATH_AMPDU_LIMIT_DEFAULT);
 
         /*
          * h/w can accept aggregates upto 16 bit lengths (65535).
@@ -507,9 +465,9 @@ static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
 }
 
 /*
- * returns the number of delimiters to be added to
+ * Returns the number of delimiters to be added to
  * meet the minimum required mpdudensity.
- * caller should make sure that the rate is  HT rate .
+ * caller should make sure that the rate is HT rate .
  */
 static int ath_compute_num_delims(struct ath_softc *sc, struct ath_atx_tid *tid,
                                   struct ath_buf *bf, u16 frmlen)
@@ -566,9 +524,7 @@ static int ath_compute_num_delims(struct ath_softc *sc, struct ath_atx_tid *tid,
         nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
         minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
 
-        /* Is frame shorter than required minimum length? */
         if (frmlen < minlen) {
-                /* Get the minimum number of delimiters required. */
                 mindelim = (minlen - frmlen) / ATH_AGGR_DELIM_SZ;
                 ndelim = max(mindelim, ndelim);
         }
@@ -577,30 +533,22 @@ static int ath_compute_num_delims(struct ath_softc *sc, struct ath_atx_tid *tid,
 }
 
 static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
-                     struct ath_atx_tid *tid, struct list_head *bf_q,
-                     struct ath_buf **bf_last, struct aggr_rifs_param *param,
-                     int *prev_frames)
+                                             struct ath_atx_tid *tid,
+                                             struct list_head *bf_q)
 {
 #define PADBYTES(_len) ((4 - ((_len) % 4)) % 4)
-        struct ath_buf *bf, *tbf, *bf_first, *bf_prev = NULL;
-        struct list_head bf_head;
-        int rl = 0, nframes = 0, ndelim;
+        struct ath_buf *bf, *bf_first, *bf_prev = NULL;
+        int rl = 0, nframes = 0, ndelim, prev_al = 0;
         u16 aggr_limit = 0, al = 0, bpad = 0,
                 al_delta, h_baw = tid->baw_size / 2;
         enum ATH_AGGR_STATUS status = ATH_AGGR_DONE;
-        int prev_al = 0;
-        INIT_LIST_HEAD(&bf_head);
-
-        BUG_ON(list_empty(&tid->buf_q));
 
         bf_first = list_first_entry(&tid->buf_q, struct ath_buf, list);
 
         do {
                 bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
 
-                /*
-                 * do not step over block-ack window
-                 */
+                /* do not step over block-ack window */
                 if (!BAW_WITHIN(tid->seq_start, tid->baw_size, bf->bf_seqno)) {
                         status = ATH_AGGR_BAW_CLOSED;
                         break;
@@ -611,29 +559,23 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
                         rl = 1;
                 }
 
-                /*
-                 * do not exceed aggregation limit
-                 */
+                /* do not exceed aggregation limit */
                 al_delta = ATH_AGGR_DELIM_SZ + bf->bf_frmlen;
 
-                if (nframes && (aggr_limit <
-                        (al + bpad + al_delta + prev_al))) {
+                if (nframes &&
+                    (aggr_limit < (al + bpad + al_delta + prev_al))) {
                         status = ATH_AGGR_LIMITED;
                         break;
                 }
 
-                /*
-                 * do not exceed subframe limit
-                 */
-                if ((nframes + *prev_frames) >=
-                    min((int)h_baw, ATH_AMPDU_SUBFRAME_DEFAULT)) {
+                /* do not exceed subframe limit */
+                if (nframes >= min((int)h_baw, ATH_AMPDU_SUBFRAME_DEFAULT)) {
                         status = ATH_AGGR_LIMITED;
                         break;
                 }
+                nframes++;
 
-                /*
-                 * add padding for previous frame to aggregation length
-                 */
+                /* add padding for previous frame to aggregation length */
                 al += bpad + al_delta;
 
                 /*
@@ -641,44 +583,25 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
                  * density for this node.
                  */
                 ndelim = ath_compute_num_delims(sc, tid, bf_first, bf->bf_frmlen);
-
                 bpad = PADBYTES(al_delta) + (ndelim << 2);
 
                 bf->bf_next = NULL;
-                bf->bf_lastfrm->bf_desc->ds_link = 0;
+                bf->bf_desc->ds_link = 0;
 
-                /*
-                 * this packet is part of an aggregate
-                 * - remove all descriptors belonging to this frame from
-                 *   software queue
-                 * - add it to block ack window
-                 * - set up descriptors for aggregation
-                 */
-                list_cut_position(&bf_head, &tid->buf_q, &bf->bf_lastfrm->list);
+                /* link buffers of this frame to the aggregate */
                 ath_tx_addto_baw(sc, tid, bf);
-
-                list_for_each_entry(tbf, &bf_head, list) {
-                        ath9k_hw_set11n_aggr_middle(sc->sc_ah,
-                                tbf->bf_desc, ndelim);
-                }
-
-                /*
-                 * link buffers of this frame to the aggregate
-                 */
-                list_splice_tail_init(&bf_head, bf_q);
-                nframes++;
-
+                ath9k_hw_set11n_aggr_middle(sc->sc_ah, bf->bf_desc, ndelim);
+                list_move_tail(&bf->list, bf_q);
                 if (bf_prev) {
                         bf_prev->bf_next = bf;
-                        bf_prev->bf_lastfrm->bf_desc->ds_link = bf->bf_daddr;
+                        bf_prev->bf_desc->ds_link = bf->bf_daddr;
                 }
                 bf_prev = bf;
-
         } while (!list_empty(&tid->buf_q));
 
         bf_first->bf_al = al;
         bf_first->bf_nframes = nframes;
-        *bf_last = bf_prev;
+
         return status;
 #undef PADBYTES
 }
@@ -686,11 +609,9 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
 static void ath_tx_sched_aggr(struct ath_softc *sc, struct ath_txq *txq,
                               struct ath_atx_tid *tid)
 {
-        struct ath_buf *bf, *tbf, *bf_last, *bf_lastaggr = NULL;
+        struct ath_buf *bf;
         enum ATH_AGGR_STATUS status;
         struct list_head bf_q;
-        struct aggr_rifs_param param = {0, 0, 0, 0, NULL};
-        int prev_frames = 0;
 
         do {
                 if (list_empty(&tid->buf_q))
@@ -698,66 +619,36 @@ static void ath_tx_sched_aggr(struct ath_softc *sc, struct ath_txq *txq,
 
                 INIT_LIST_HEAD(&bf_q);
 
-                status = ath_tx_form_aggr(sc, tid, &bf_q, &bf_lastaggr, &param,
-                                          &prev_frames);
+                status = ath_tx_form_aggr(sc, tid, &bf_q);
 
                 /*
-                 * no frames picked up to be aggregated; block-ack
-                 * window is not open
+                 * no frames picked up to be aggregated;
+                 * block-ack window is not open.
                  */
                 if (list_empty(&bf_q))
                         break;
 
                 bf = list_first_entry(&bf_q, struct ath_buf, list);
-                bf_last = list_entry(bf_q.prev, struct ath_buf, list);
-                bf->bf_lastbf = bf_last;
+                bf->bf_lastbf = list_entry(bf_q.prev, struct ath_buf, list);
 
-                /*
-                 * if only one frame, send as non-aggregate
-                 */
+                /* if only one frame, send as non-aggregate */
                 if (bf->bf_nframes == 1) {
-                        ASSERT(bf->bf_lastfrm == bf_last);
-
                         bf->bf_state.bf_type &= ~BUF_AGGR;
-                        /*
-                         * clear aggr bits for every descriptor
-                         * XXX TODO: is there a way to optimize it?
-                         */
-                        list_for_each_entry(tbf, &bf_q, list) {
-                                ath9k_hw_clr11n_aggr(sc->sc_ah, tbf->bf_desc);
-                        }
-
+                        ath9k_hw_clr11n_aggr(sc->sc_ah, bf->bf_desc);
                         ath_buf_set_rate(sc, bf);
                         ath_tx_txqaddbuf(sc, txq, &bf_q);
                         continue;
                 }
 
-                /*
-                 * setup first desc with rate and aggr info
-                 */
+                /* setup first desc of aggregate */
                 bf->bf_state.bf_type |= BUF_AGGR;
                 ath_buf_set_rate(sc, bf);
                 ath9k_hw_set11n_aggr_first(sc->sc_ah, bf->bf_desc, bf->bf_al);
 
-                /*
-                 * anchor last frame of aggregate correctly
-                 */
-                ASSERT(bf_lastaggr);
-                ASSERT(bf_lastaggr->bf_lastfrm == bf_last);
-                tbf = bf_lastaggr;
-                ath9k_hw_set11n_aggr_last(sc->sc_ah, tbf->bf_desc);
-
-                /* XXX: We don't enter into this loop, consider removing this */
-                while (!list_empty(&bf_q) && !list_is_last(&tbf->list, &bf_q)) {
-                        tbf = list_entry(tbf->list.next, struct ath_buf, list);
-                        ath9k_hw_set11n_aggr_last(sc->sc_ah, tbf->bf_desc);
-                }
+                /* anchor last desc of aggregate */
+                ath9k_hw_set11n_aggr_last(sc->sc_ah, bf->bf_lastbf->bf_desc);
 
                 txq->axq_aggr_depth++;
-
-                /*
-                 * Normal aggregate, queue to hardware
-                 */
                 ath_tx_txqaddbuf(sc, txq, &bf_q);
 
         } while (txq->axq_depth < ATH_AGGR_MIN_QDEPTH &&
@@ -812,19 +703,17 @@ int ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid)
                          */
                         break;
                 }
-                list_cut_position(&bf_head,
-                        &txtid->buf_q, &bf->bf_lastfrm->list);
+                list_move_tail(&bf->list, &bf_head);
                 ath_tx_update_baw(sc, txtid, bf->bf_seqno);
                 ath_tx_complete_buf(sc, bf, &bf_head, 0, 0);
         }
+        spin_unlock_bh(&txq->axq_lock);
 
         if (txtid->baw_head != txtid->baw_tail) {
-                spin_unlock_bh(&txq->axq_lock);
                 txtid->state |= AGGR_CLEANUP;
         } else {
                 txtid->state &= ~AGGR_ADDBA_COMPLETE;
                 txtid->addba_exchangeattempts = 0;
-                spin_unlock_bh(&txq->axq_lock);
                 ath_tx_flush_tid(sc, txtid);
         }
 
@@ -1130,7 +1019,7 @@ void ath_draintxq(struct ath_softc *sc, struct ath_txq *txq, bool retry_tx)
                 spin_unlock_bh(&txq->axq_lock);
 
                 if (bf_isampdu(bf))
-                        ath_tx_complete_aggr_rifs(sc, txq, bf, &bf_head, 0);
+                        ath_tx_complete_aggr(sc, txq, bf, &bf_head, 0);
                 else
                         ath_tx_complete_buf(sc, bf, &bf_head, 0, 0);
         }
@@ -1326,8 +1215,6 @@ static void ath_tx_send_ampdu(struct ath_softc *sc, struct ath_atx_tid *tid,
 {
         struct ath_buf *bf;
 
-        BUG_ON(list_empty(bf_head));
-
         bf = list_first_entry(bf_head, struct ath_buf, list);
         bf->bf_state.bf_type |= BUF_AMPDU;
 
@@ -1345,7 +1232,7 @@ static void ath_tx_send_ampdu(struct ath_softc *sc, struct ath_atx_tid *tid,
                  * Add this frame to software queue for scheduling later
                  * for aggregation.
                  */
-                list_splice_tail_init(bf_head, &tid->buf_q);
+                list_move_tail(&bf->list, &tid->buf_q);
                 ath_tx_queue_tid(txctl->txq, tid);
                 return;
         }
@@ -1355,11 +1242,9 @@ static void ath_tx_send_ampdu(struct ath_softc *sc, struct ath_atx_tid *tid,
 
         /* Queue to h/w without aggregation */
         bf->bf_nframes = 1;
-        bf->bf_lastbf = bf->bf_lastfrm; /* one single frame */
+        bf->bf_lastbf = bf;
         ath_buf_set_rate(sc, bf);
         ath_tx_txqaddbuf(sc, txctl->txq, bf_head);
-
-        return;
 }
 
 static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
@@ -1368,8 +1253,6 @@ static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
 {
         struct ath_buf *bf;
 
-        BUG_ON(list_empty(bf_head));
-
         bf = list_first_entry(bf_head, struct ath_buf, list);
         bf->bf_state.bf_type &= ~BUF_AMPDU;
 
@@ -1377,7 +1260,7 @@ static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
         INCR(tid->seq_start, IEEE80211_SEQ_MAX);
 
         bf->bf_nframes = 1;
-        bf->bf_lastbf = bf->bf_lastfrm;
+        bf->bf_lastbf = bf;
         ath_buf_set_rate(sc, bf);
         ath_tx_txqaddbuf(sc, txq, bf_head);
 }
@@ -1770,8 +1653,6 @@ static void ath_tx_start_dma(struct ath_softc *sc, struct ath_buf *bf,
                             true,       /* last segment */
                             ds);        /* first descriptor */
 
-        bf->bf_lastfrm = bf;
-
         spin_lock_bh(&txctl->txq->axq_lock);
 
         if (bf_isht(bf) && (sc->sc_flags & SC_OP_TXAGGR) &&
@@ -2155,7 +2036,7 @@ static void ath_tx_processq(struct ath_softc *sc, struct ath_txq *txq)
                 ath_tx_rc_status(bf, ds, nbad);
 
                 if (bf_isampdu(bf))
-                        ath_tx_complete_aggr_rifs(sc, txq, bf, &bf_head, txok);
+                        ath_tx_complete_aggr(sc, txq, bf, &bf_head, txok);
                 else
                         ath_tx_complete_buf(sc, bf, &bf_head, txok, 0);