diff options
author | Felix Fietkau <nbd@openwrt.org> | 2013-05-18 21:28:15 +0200 |
---|---|---|
committer | John W. Linville <linville@tuxdriver.com> | 2013-05-22 14:28:44 -0400 |
commit | 08c96abd611beadf2af414a306fe0fb02ba706ff (patch) | |
tree | 2ee91910a79083004eacad4a05fe0699d4a7e534 | |
parent | 323a98db4d51e4fefc74290adfb5493047cbbe22 (diff) |
ath9k: prevent aggregation session deadlocks
Waiting for all subframes of an existing aggregation session to drain
before allowing mac80211 to start a new one is fragile and deadlocks
caused by this behavior have been observed.
Since mac80211 has proper synchronization for aggregation session
start/stop handling, a better approach to session handling is to simply
allow mac80211 to start a new session at any time. This requires
changing the code to discard any packets outside of the BlockAck window
in the A-MPDU software retry code.
This patch implements the above and also simplifies the code.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r-- | drivers/net/wireless/ath/ath9k/ath9k.h | 14 | ||||
-rw-r--r-- | drivers/net/wireless/ath/ath9k/main.c | 3 | ||||
-rw-r--r-- | drivers/net/wireless/ath/ath9k/rc.c | 5 | ||||
-rw-r--r-- | drivers/net/wireless/ath/ath9k/xmit.c | 138 |
4 files changed, 46 insertions, 114 deletions
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h index 366002f266f..42b03dc39d1 100644 --- a/drivers/net/wireless/ath/ath9k/ath9k.h +++ b/drivers/net/wireless/ath/ath9k/ath9k.h @@ -251,10 +251,9 @@ struct ath_atx_tid { int tidno; int baw_head; /* first un-acked tx buffer */ int baw_tail; /* next unused tx buffer slot */ - int sched; - int paused; - u8 state; - bool stop_cb; + bool sched; + bool paused; + bool active; }; struct ath_node { @@ -275,10 +274,6 @@ struct ath_node { #endif }; -#define AGGR_CLEANUP BIT(1) -#define AGGR_ADDBA_COMPLETE BIT(2) -#define AGGR_ADDBA_PROGRESS BIT(3) - struct ath_tx_control { struct ath_txq *txq; struct ath_node *an; @@ -352,8 +347,7 @@ void ath_tx_tasklet(struct ath_softc *sc); void ath_tx_edma_tasklet(struct ath_softc *sc); int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid, u16 *ssn); -bool ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid, - bool flush); +void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid); void ath_tx_aggr_resume(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid); void ath_tx_aggr_wakeup(struct ath_softc *sc, struct ath_node *an); diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index 2382d1262e7..5092ecae770 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -1709,7 +1709,8 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw, flush = true; case IEEE80211_AMPDU_TX_STOP_CONT: ath9k_ps_wakeup(sc); - if (ath_tx_aggr_stop(sc, sta, tid, flush)) + ath_tx_aggr_stop(sc, sta, tid); + if (!flush) ieee80211_stop_tx_ba_cb_irqsafe(vif, sta->addr, tid); ath9k_ps_restore(sc); break; diff --git a/drivers/net/wireless/ath/ath9k/rc.c b/drivers/net/wireless/ath/ath9k/rc.c index aa4d368d8d3..7eb1f4b458e 100644 --- a/drivers/net/wireless/ath/ath9k/rc.c +++ b/drivers/net/wireless/ath/ath9k/rc.c @@ -1227,10 +1227,7 @@ static bool ath_tx_aggr_check(struct ath_softc *sc, struct ieee80211_sta *sta, return false; txtid = ATH_AN_2_TID(an, tidno); - - if (!(txtid->state & (AGGR_ADDBA_COMPLETE | AGGR_ADDBA_PROGRESS))) - return true; - return false; + return !txtid->active; } diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c index 14bb3354ea6..1c9b1bac8b0 100644 --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -125,24 +125,6 @@ static void ath_tx_queue_tid(struct ath_txq *txq, struct ath_atx_tid *tid) list_add_tail(&ac->list, &txq->axq_acq); } -static void ath_tx_resume_tid(struct ath_softc *sc, struct ath_atx_tid *tid) -{ - struct ath_txq *txq = tid->ac->txq; - - WARN_ON(!tid->paused); - - ath_txq_lock(sc, txq); - tid->paused = false; - - if (skb_queue_empty(&tid->buf_q)) - goto unlock; - - ath_tx_queue_tid(txq, tid); - ath_txq_schedule(sc, txq); -unlock: - ath_txq_unlock_complete(sc, txq); -} - static struct ath_frame_info *get_frame_info(struct sk_buff *skb) { struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb); @@ -164,20 +146,7 @@ static void ath_set_rates(struct ieee80211_vif *vif, struct ieee80211_sta *sta, ARRAY_SIZE(bf->rates)); } -static void ath_tx_clear_tid(struct ath_softc *sc, struct ath_atx_tid *tid) -{ - tid->state &= ~AGGR_ADDBA_COMPLETE; - tid->state &= ~AGGR_CLEANUP; - if (!tid->stop_cb) - return; - - ieee80211_start_tx_ba_cb_irqsafe(tid->an->vif, tid->an->sta->addr, - tid->tidno); - tid->stop_cb = false; -} - -static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid, - bool flush_packets) +static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid) { struct ath_txq *txq = tid->ac->txq; struct sk_buff *skb; @@ -194,15 +163,16 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid, while ((skb = __skb_dequeue(&tid->buf_q))) { fi = get_frame_info(skb); bf = fi->bf; - if (!bf && !flush_packets) - bf = ath_tx_setup_buffer(sc, txq, tid, skb); if (!bf) { - ieee80211_free_txskb(sc->hw, skb); - continue; + bf = ath_tx_setup_buffer(sc, txq, tid, skb); + if (!bf) { + ieee80211_free_txskb(sc->hw, skb); + continue; + } } - if (fi->retries || flush_packets) { + if (fi->retries) { list_add_tail(&bf->list, &bf_head); ath_tx_update_baw(sc, tid, bf->bf_state.seqno); ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0); @@ -213,10 +183,7 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid, } } - if (tid->baw_head == tid->baw_tail) - ath_tx_clear_tid(sc, tid); - - if (sendbar && !flush_packets) { + if (sendbar) { ath_txq_unlock(sc, txq); ath_send_bar(tid, tid->seq_start); ath_txq_lock(sc, txq); @@ -499,19 +466,19 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq, tx_info = IEEE80211_SKB_CB(skb); fi = get_frame_info(skb); - if (ATH_BA_ISSET(ba, ATH_BA_INDEX(seq_st, seqno))) { + if (!BAW_WITHIN(tid->seq_start, tid->baw_size, seqno)) { + /* + * Outside of the current BlockAck window, + * maybe part of a previous session + */ + txfail = 1; + } else if (ATH_BA_ISSET(ba, ATH_BA_INDEX(seq_st, seqno))) { /* transmit completion, subframe is * acked by block ack */ acked_cnt++; } else if (!isaggr && txok) { /* transmit completion */ acked_cnt++; - } else if (tid->state & AGGR_CLEANUP) { - /* - * cleanup in progress, just fail - * the un-acked sub-frames - */ - txfail = 1; } else if (flush) { txpending = 1; } else if (fi->retries < ATH_MAX_SW_RETRIES) { @@ -535,7 +502,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq, if (bf_next != NULL || !bf_last->bf_stale) list_move_tail(&bf->list, &bf_head); - if (!txpending || (tid->state & AGGR_CLEANUP)) { + if (!txpending) { /* * complete the acked-ones/xretried ones; update * block-ack window @@ -609,9 +576,6 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq, ath_txq_lock(sc, txq); } - if (tid->state & AGGR_CLEANUP) - ath_tx_flush_tid(sc, tid, false); - rcu_read_unlock(); if (needreset) @@ -1244,9 +1208,6 @@ int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta, an = (struct ath_node *)sta->drv_priv; txtid = ATH_AN_2_TID(an, tid); - if (txtid->state & (AGGR_CLEANUP | AGGR_ADDBA_COMPLETE)) - return -EAGAIN; - /* update ampdu factor/density, they may have changed. This may happen * in HT IBSS when a beacon with HT-info is received after the station * has already been added. @@ -1258,7 +1219,7 @@ int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta, an->mpdudensity = density; } - txtid->state |= AGGR_ADDBA_PROGRESS; + txtid->active = true; txtid->paused = true; *ssn = txtid->seq_start = txtid->seq_next; txtid->bar_index = -1; @@ -1269,45 +1230,17 @@ int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta, return 0; } -bool ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid, - bool flush) +void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid) { struct ath_node *an = (struct ath_node *)sta->drv_priv; struct ath_atx_tid *txtid = ATH_AN_2_TID(an, tid); struct ath_txq *txq = txtid->ac->txq; - bool ret = !flush; - - if (flush) - txtid->stop_cb = false; - - if (txtid->state & AGGR_CLEANUP) - return false; - - if (!(txtid->state & AGGR_ADDBA_COMPLETE)) { - txtid->state &= ~AGGR_ADDBA_PROGRESS; - return ret; - } ath_txq_lock(sc, txq); + txtid->active = false; txtid->paused = true; - - /* - * If frames are still being transmitted for this TID, they will be - * cleaned up during tx completion. To prevent race conditions, this - * TID can only be reused after all in-progress subframes have been - * completed. - */ - if (txtid->baw_head != txtid->baw_tail) { - txtid->state |= AGGR_CLEANUP; - ret = false; - txtid->stop_cb = !flush; - } else { - txtid->state &= ~AGGR_ADDBA_COMPLETE; - } - - ath_tx_flush_tid(sc, txtid, flush); + ath_tx_flush_tid(sc, txtid); ath_txq_unlock_complete(sc, txq); - return ret; } void ath_tx_aggr_sleep(struct ieee80211_sta *sta, struct ath_softc *sc, @@ -1371,18 +1304,28 @@ void ath_tx_aggr_wakeup(struct ath_softc *sc, struct ath_node *an) } } -void ath_tx_aggr_resume(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid) +void ath_tx_aggr_resume(struct ath_softc *sc, struct ieee80211_sta *sta, + u16 tidno) { - struct ath_atx_tid *txtid; + struct ath_atx_tid *tid; struct ath_node *an; + struct ath_txq *txq; an = (struct ath_node *)sta->drv_priv; + tid = ATH_AN_2_TID(an, tidno); + txq = tid->ac->txq; - txtid = ATH_AN_2_TID(an, tid); - txtid->baw_size = IEEE80211_MIN_AMPDU_BUF << sta->ht_cap.ampdu_factor; - txtid->state |= AGGR_ADDBA_COMPLETE; - txtid->state &= ~AGGR_ADDBA_PROGRESS; - ath_tx_resume_tid(sc, txtid); + ath_txq_lock(sc, txq); + + tid->baw_size = IEEE80211_MIN_AMPDU_BUF << sta->ht_cap.ampdu_factor; + tid->paused = false; + + if (!skb_queue_empty(&tid->buf_q)) { + ath_tx_queue_tid(txq, tid); + ath_txq_schedule(sc, txq); + } + + ath_txq_unlock_complete(sc, txq); } /********************/ @@ -2431,13 +2374,10 @@ void ath_tx_node_init(struct ath_softc *sc, struct ath_node *an) tid->baw_head = tid->baw_tail = 0; tid->sched = false; tid->paused = false; - tid->state &= ~AGGR_CLEANUP; + tid->active = false; __skb_queue_head_init(&tid->buf_q); acno = TID_TO_WME_AC(tidno); tid->ac = &an->ac[acno]; - tid->state &= ~AGGR_ADDBA_COMPLETE; - tid->state &= ~AGGR_ADDBA_PROGRESS; - tid->stop_cb = false; } for (acno = 0, ac = &an->ac[acno]; @@ -2474,7 +2414,7 @@ void ath_tx_node_cleanup(struct ath_softc *sc, struct ath_node *an) } ath_tid_drain(sc, txq, tid); - ath_tx_clear_tid(sc, tid); + tid->active = false; ath_txq_unlock(sc, txq); } |