From: Johannes Berg <johannes.berg@xxxxxxxxx> To prepare for allowing drivers to sleep in ampdu_action, change the locking in the TX aggregation code to use the mutex the RX part already uses. The spinlock is still necessary around some code to avoid races with TX, but now we can also synchronize_net() to avoid getting an inconsistent sequence number. Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> --- net/mac80211/agg-tx.c | 90 +++++++++++++++++++++++++--------------------- net/mac80211/driver-ops.h | 3 + net/mac80211/ht.c | 6 --- 3 files changed, 54 insertions(+), 45 deletions(-) --- wireless-testing.orig/net/mac80211/agg-tx.c 2010-06-07 12:22:12.000000000 +0200 +++ wireless-testing/net/mac80211/agg-tx.c 2010-06-07 12:32:28.000000000 +0200 @@ -140,18 +140,25 @@ int ___ieee80211_stop_tx_ba_session(stru struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid]; int ret; - lockdep_assert_held(&sta->lock); + lockdep_assert_held(&sta->ampdu_mlme.mtx); - if (WARN_ON(!tid_tx)) + spin_lock_bh(&sta->lock); + + if (!tid_tx) { + spin_unlock_bh(&sta->lock); return -ENOENT; + } if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) { /* not even started yet! */ rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL); + spin_unlock_bh(&sta->lock); call_rcu(&tid_tx->rcu_head, kfree_tid_tx); return 0; } + spin_unlock_bh(&sta->lock); + #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n", sta->sta.addr, tid); @@ -281,10 +288,11 @@ void ieee80211_tx_ba_session_handle_star clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state); /* - * This might be off by one due to a race that we can't - * really prevent here without synchronize_net() which - * can't be called now. + * make sure no packets are being processed to get + * valid starting sequence number */ + synchronize_net(); + start_seq_num = sta->tid_seq[tid] >> 4; ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START, @@ -294,7 +302,10 @@ void ieee80211_tx_ba_session_handle_star printk(KERN_DEBUG "BA request denied - HW unavailable for" " tid %d\n", tid); #endif + spin_lock_bh(&sta->lock); rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL); + spin_unlock_bh(&sta->lock); + ieee80211_wake_queue_agg(local, tid); call_rcu(&tid_tx->rcu_head, kfree_tid_tx); return; @@ -445,16 +456,25 @@ ieee80211_agg_splice_finish(struct ieee8 ieee80211_wake_queue_agg(local, tid); } -/* caller must hold sta->lock */ static void ieee80211_agg_tx_operational(struct ieee80211_local *local, struct sta_info *sta, u16 tid) { - lockdep_assert_held(&sta->lock); + lockdep_assert_held(&sta->ampdu_mlme.mtx); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid); #endif + drv_ampdu_action(local, sta->sdata, + IEEE80211_AMPDU_TX_OPERATIONAL, + &sta->sta, tid, NULL); + + /* + * synchronize with TX path, while splicing the TX path + * should block so it won't put more packets onto pending. + */ + spin_lock_bh(&sta->lock); + ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid); /* * Now mark as operational. This will be visible @@ -464,9 +484,7 @@ static void ieee80211_agg_tx_operational set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state); ieee80211_agg_splice_finish(local, tid); - drv_ampdu_action(local, sta->sdata, - IEEE80211_AMPDU_TX_OPERATIONAL, - &sta->sta, tid, NULL); + spin_unlock_bh(&sta->lock); } void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid) @@ -486,37 +504,35 @@ void ieee80211_start_tx_ba_cb(struct iee return; } - rcu_read_lock(); + mutex_lock(&local->sta_mtx); sta = sta_info_get(sdata, ra); if (!sta) { - rcu_read_unlock(); + mutex_unlock(&local->sta_mtx); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Could not find station: %pM\n", ra); #endif return; } - spin_lock_bh(&sta->lock); + mutex_lock(&sta->ampdu_mlme.mtx); tid_tx = sta->ampdu_mlme.tid_tx[tid]; if (WARN_ON(!tid_tx)) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "addBA was not requested!\n"); #endif - spin_unlock_bh(&sta->lock); - rcu_read_unlock(); - return; + goto unlock; } if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))) - goto out; + goto unlock; if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) ieee80211_agg_tx_operational(local, sta, tid); - out: - spin_unlock_bh(&sta->lock); - rcu_read_unlock(); + unlock: + mutex_unlock(&sta->ampdu_mlme.mtx); + mutex_unlock(&local->sta_mtx); } void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif, @@ -548,21 +564,14 @@ EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_i int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid, enum ieee80211_back_parties initiator) { - struct tid_ampdu_tx *tid_tx; int ret; - spin_lock_bh(&sta->lock); - tid_tx = sta->ampdu_mlme.tid_tx[tid]; - - if (!tid_tx) { - ret = -ENOENT; - goto unlock; - } + mutex_lock(&sta->ampdu_mlme.mtx); ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator); - unlock: - spin_unlock_bh(&sta->lock); + mutex_unlock(&sta->ampdu_mlme.mtx); + return ret; } @@ -627,16 +636,17 @@ void ieee80211_stop_tx_ba_cb(struct ieee ra, tid); #endif /* CONFIG_MAC80211_HT_DEBUG */ - rcu_read_lock(); + mutex_lock(&local->sta_mtx); + sta = sta_info_get(sdata, ra); if (!sta) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Could not find station: %pM\n", ra); #endif - rcu_read_unlock(); - return; + goto unlock; } + mutex_lock(&sta->ampdu_mlme.mtx); spin_lock_bh(&sta->lock); tid_tx = sta->ampdu_mlme.tid_tx[tid]; @@ -644,9 +654,7 @@ void ieee80211_stop_tx_ba_cb(struct ieee #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n"); #endif - spin_unlock_bh(&sta->lock); - rcu_read_unlock(); - return; + goto unlock_sta; } if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR) @@ -672,8 +680,11 @@ void ieee80211_stop_tx_ba_cb(struct ieee call_rcu(&tid_tx->rcu_head, kfree_tid_tx); + unlock_sta: spin_unlock_bh(&sta->lock); - rcu_read_unlock(); + mutex_unlock(&sta->ampdu_mlme.mtx); + unlock: + mutex_unlock(&local->sta_mtx); } void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif, @@ -714,10 +725,9 @@ void ieee80211_process_addba_resp(struct capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab); tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2; - spin_lock_bh(&sta->lock); + mutex_lock(&sta->ampdu_mlme.mtx); tid_tx = sta->ampdu_mlme.tid_tx[tid]; - if (!tid_tx) goto out; @@ -751,5 +761,5 @@ void ieee80211_process_addba_resp(struct } out: - spin_unlock_bh(&sta->lock); + mutex_unlock(&sta->ampdu_mlme.mtx); } --- wireless-testing.orig/net/mac80211/ht.c 2010-06-07 12:22:08.000000000 +0200 +++ wireless-testing/net/mac80211/ht.c 2010-06-07 12:22:13.000000000 +0200 @@ -136,11 +136,7 @@ void ieee80211_ba_session_work(struct wo ___ieee80211_stop_rx_ba_session( sta, tid, WLAN_BACK_RECIPIENT, WLAN_REASON_QSTA_TIMEOUT); - } - mutex_unlock(&sta->ampdu_mlme.mtx); - spin_lock_bh(&sta->lock); - for (tid = 0; tid < STA_TID_NUM; tid++) { tid_tx = sta->ampdu_mlme.tid_tx[tid]; if (!tid_tx) continue; @@ -152,7 +148,7 @@ void ieee80211_ba_session_work(struct wo ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR); } - spin_unlock_bh(&sta->lock); + mutex_unlock(&sta->ampdu_mlme.mtx); } void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata, --- wireless-testing.orig/net/mac80211/driver-ops.h 2010-06-07 12:22:20.000000000 +0200 +++ wireless-testing/net/mac80211/driver-ops.h 2010-06-07 12:22:31.000000000 +0200 @@ -349,6 +349,9 @@ static inline int drv_ampdu_action(struc u16 *ssn) { int ret = -EOPNOTSUPP; + + might_sleep(); + local_bh_disable(); if (local->ops->ampdu_action) ret = local->ops->ampdu_action(&local->hw, &sdata->vif, action, -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html