From 003e5236a1fcab3fc4576fe643e31a3d83027256 Mon Sep 17 00:00:00 2001 From: Andrei Otcheretianski Date: Sun, 25 May 2014 17:24:22 +0300 Subject: [PATCH] iwlwifi: mvm: Use CS tx block bit for AP/GO An AP/GO may perform the channel switch slightly before its stations. This scenario may result in packet loss, since the transmission may start before the client is actually on a new channel. In order to prevent potential packet loss disable tx to all the stations when the channel switch flow starts. Clear the disable_tx bit when a station is seen on a target channel, or after IWL_MVM_CS_UNBLOCK_TX_TIMEOUT beacons on a new channel. In addition call ieee80211_sta_block_awake in order to inform mac80211 that the frames for this station should be buffered. Signed-off-by: Andrei Otcheretianski Reviewed-by: Johannes Berg Signed-off-by: Emmanuel Grumbach --- drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c | 25 ++++++++++ drivers/net/wireless/iwlwifi/mvm/mac80211.c | 11 +++++ drivers/net/wireless/iwlwifi/mvm/mvm.h | 8 +++ drivers/net/wireless/iwlwifi/mvm/rx.c | 17 +++++++ drivers/net/wireless/iwlwifi/mvm/sta.c | 54 +++++++++++++++++++++ drivers/net/wireless/iwlwifi/mvm/sta.h | 10 ++++ drivers/net/wireless/iwlwifi/mvm/tx.c | 14 ++++-- 7 files changed, 136 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c b/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c index a176d008dab1..96b9cf8137e7 100644 --- a/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c +++ b/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c @@ -1237,6 +1237,7 @@ int iwl_mvm_rx_beacon_notif(struct iwl_mvm *mvm, struct iwl_rx_packet *pkt = rxb_addr(rxb); struct iwl_mvm_tx_resp *beacon_notify_hdr; struct ieee80211_vif *csa_vif; + struct ieee80211_vif *tx_blocked_vif; u64 tsf; lockdep_assert_held(&mvm->mutex); @@ -1267,6 +1268,30 @@ int iwl_mvm_rx_beacon_notif(struct iwl_mvm *mvm, if (unlikely(csa_vif && csa_vif->csa_active)) iwl_mvm_csa_count_down(mvm, csa_vif, mvm->ap_last_beacon_gp2); + tx_blocked_vif = rcu_dereference_protected(mvm->csa_tx_blocked_vif, + lockdep_is_held(&mvm->mutex)); + if (unlikely(tx_blocked_vif)) { + struct iwl_mvm_vif *mvmvif = + iwl_mvm_vif_from_mac80211(tx_blocked_vif); + + /* + * The channel switch is started and we have blocked the + * stations. If this is the first beacon (the timeout wasn't + * set), set the unblock timeout, otherwise countdown + */ + if (!mvm->csa_tx_block_bcn_timeout) + mvm->csa_tx_block_bcn_timeout = + IWL_MVM_CS_UNBLOCK_TX_TIMEOUT; + else + mvm->csa_tx_block_bcn_timeout--; + + /* Check if the timeout is expired, and unblock tx */ + if (mvm->csa_tx_block_bcn_timeout == 0) { + iwl_mvm_modify_all_sta_disable_tx(mvm, mvmvif, false); + RCU_INIT_POINTER(mvm->csa_tx_blocked_vif, NULL); + } + } + return 0; } diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c index 4a0350fc4b4e..5ed6fb32087c 100644 --- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c +++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c @@ -1614,6 +1614,11 @@ static void iwl_mvm_stop_ap_ibss(struct ieee80211_hw *hw, RCU_INIT_POINTER(mvm->csa_vif, NULL); } + if (rcu_access_pointer(mvm->csa_tx_blocked_vif) == vif) { + RCU_INIT_POINTER(mvm->csa_tx_blocked_vif, NULL); + mvm->csa_tx_block_bcn_timeout = 0; + } + mvmvif->ap_ibss_active = false; mvm->ap_last_beacon_gp2 = 0; @@ -2491,6 +2496,12 @@ static void __iwl_mvm_unassign_vif_chanctx(struct iwl_mvm *mvm, if (!vif->csa_active || !mvmvif->ap_ibss_active) goto out; + /* Set CS bit on all the stations */ + iwl_mvm_modify_all_sta_disable_tx(mvm, mvmvif, true); + + /* Save blocked iface, the timeout is set on the next beacon */ + rcu_assign_pointer(mvm->csa_tx_blocked_vif, vif); + mvmvif->ap_ibss_active = false; break; case NL80211_IFTYPE_STATION: diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h index db496c5c73fc..7b308c4834f6 100644 --- a/drivers/net/wireless/iwlwifi/mvm/mvm.h +++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h @@ -95,6 +95,12 @@ */ #define IWL_MVM_CHANNEL_SWITCH_MARGIN 4 +/* + * Number of beacons to transmit on a new channel until we unblock tx to + * the stations, even if we didn't identify them on a new channel + */ +#define IWL_MVM_CS_UNBLOCK_TX_TIMEOUT 3 + enum iwl_mvm_tx_fifo { IWL_MVM_TX_FIFO_BK = 0, IWL_MVM_TX_FIFO_BE, @@ -671,6 +677,8 @@ struct iwl_mvm { bool ps_disabled; struct ieee80211_vif __rcu *csa_vif; + struct ieee80211_vif __rcu *csa_tx_blocked_vif; + u8 csa_tx_block_bcn_timeout; /* system time of last beacon (for AP/GO interface) */ u32 ap_last_beacon_gp2; diff --git a/drivers/net/wireless/iwlwifi/mvm/rx.c b/drivers/net/wireless/iwlwifi/mvm/rx.c index cf7276967acd..4b98987fc413 100644 --- a/drivers/net/wireless/iwlwifi/mvm/rx.c +++ b/drivers/net/wireless/iwlwifi/mvm/rx.c @@ -258,6 +258,23 @@ int iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb, memset(&rx_status, 0, sizeof(rx_status)); + /* + * We have tx blocked stations (with CS bit). If we heard frames from + * a blocked station on a new channel we can TX to it again. + */ + if (unlikely(mvm->csa_tx_block_bcn_timeout)) { + struct ieee80211_sta *sta; + + rcu_read_lock(); + + sta = ieee80211_find_sta( + rcu_dereference(mvm->csa_tx_blocked_vif), hdr->addr2); + if (sta) + iwl_mvm_sta_modify_disable_tx_ap(mvm, sta, false); + + rcu_read_unlock(); + } + /* * drop the packet if it has failed being decrypted by HW */ diff --git a/drivers/net/wireless/iwlwifi/mvm/sta.c b/drivers/net/wireless/iwlwifi/mvm/sta.c index d3a6cf7558eb..812813964847 100644 --- a/drivers/net/wireless/iwlwifi/mvm/sta.c +++ b/drivers/net/wireless/iwlwifi/mvm/sta.c @@ -1468,3 +1468,57 @@ void iwl_mvm_sta_modify_disable_tx(struct iwl_mvm *mvm, if (ret) IWL_ERR(mvm, "Failed to send ADD_STA command (%d)\n", ret); } + +void iwl_mvm_sta_modify_disable_tx_ap(struct iwl_mvm *mvm, + struct ieee80211_sta *sta, + bool disable) +{ + struct iwl_mvm_sta *mvm_sta = iwl_mvm_sta_from_mac80211(sta); + + spin_lock_bh(&mvm_sta->lock); + + if (mvm_sta->disable_tx == disable) { + spin_unlock_bh(&mvm_sta->lock); + return; + } + + mvm_sta->disable_tx = disable; + + /* + * Tell mac80211 to start/stop queueing tx for this station, + * but don't stop queueing if there are still pending frames + * for this station. + */ + if (disable || !atomic_read(&mvm->pending_frames[mvm_sta->sta_id])) + ieee80211_sta_block_awake(mvm->hw, sta, disable); + + iwl_mvm_sta_modify_disable_tx(mvm, mvm_sta, disable); + + spin_unlock_bh(&mvm_sta->lock); +} + +void iwl_mvm_modify_all_sta_disable_tx(struct iwl_mvm *mvm, + struct iwl_mvm_vif *mvmvif, + bool disable) +{ + struct ieee80211_sta *sta; + struct iwl_mvm_sta *mvm_sta; + int i; + + lockdep_assert_held(&mvm->mutex); + + /* Block/unblock all the stations of the given mvmvif */ + for (i = 0; i < IWL_MVM_STATION_COUNT; i++) { + sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[i], + lockdep_is_held(&mvm->mutex)); + if (IS_ERR_OR_NULL(sta)) + continue; + + mvm_sta = iwl_mvm_sta_from_mac80211(sta); + if (mvm_sta->mac_id_n_color != + FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color)) + continue; + + iwl_mvm_sta_modify_disable_tx_ap(mvm, sta, disable); + } +} diff --git a/drivers/net/wireless/iwlwifi/mvm/sta.h b/drivers/net/wireless/iwlwifi/mvm/sta.h index 10c1a5352651..3b1c8bd6cb54 100644 --- a/drivers/net/wireless/iwlwifi/mvm/sta.h +++ b/drivers/net/wireless/iwlwifi/mvm/sta.h @@ -73,6 +73,7 @@ #include "rs.h" struct iwl_mvm; +struct iwl_mvm_vif; /** * DOC: station table - introduction @@ -295,6 +296,7 @@ static inline u16 iwl_mvm_tid_queued(struct iwl_mvm_tid_data *tid_data) * @tid_data: per tid data. Look at %iwl_mvm_tid_data. * @tx_protection: reference counter for controlling the Tx protection. * @tt_tx_protection: is thermal throttling enable Tx protection? + * @disable_tx: is tx to this STA disabled? * * When mac80211 creates a station it reserves some space (hw->sta_data_size) * in the structure for use by driver. This structure is placed in that @@ -317,6 +319,8 @@ struct iwl_mvm_sta { /* Temporary, until the new TLC will control the Tx protection */ s8 tx_protection; bool tt_tx_protection; + + bool disable_tx; }; static inline struct iwl_mvm_sta * @@ -406,5 +410,11 @@ int iwl_mvm_drain_sta(struct iwl_mvm *mvm, struct iwl_mvm_sta *mvmsta, bool drain); void iwl_mvm_sta_modify_disable_tx(struct iwl_mvm *mvm, struct iwl_mvm_sta *mvmsta, bool disable); +void iwl_mvm_sta_modify_disable_tx_ap(struct iwl_mvm *mvm, + struct ieee80211_sta *sta, + bool disable); +void iwl_mvm_modify_all_sta_disable_tx(struct iwl_mvm *mvm, + struct iwl_mvm_vif *mvmvif, + bool disable); #endif /* __sta_h__ */ diff --git a/drivers/net/wireless/iwlwifi/mvm/tx.c b/drivers/net/wireless/iwlwifi/mvm/tx.c index fa87a4ba25ec..f5c0982d297c 100644 --- a/drivers/net/wireless/iwlwifi/mvm/tx.c +++ b/drivers/net/wireless/iwlwifi/mvm/tx.c @@ -727,13 +727,21 @@ static void iwl_mvm_rx_tx_cmd_single(struct iwl_mvm *mvm, goto out; if (mvmsta && mvmsta->vif->type == NL80211_IFTYPE_AP) { + /* - * If there are no pending frames for this STA, notify - * mac80211 that this station can go to sleep in its + * If there are no pending frames for this STA and + * the tx to this station is not disabled, notify + * mac80211 that this station can now wake up in its * STA table. * If mvmsta is not NULL, sta is valid. */ - ieee80211_sta_block_awake(mvm->hw, sta, false); + + spin_lock_bh(&mvmsta->lock); + + if (!mvmsta->disable_tx) + ieee80211_sta_block_awake(mvm->hw, sta, false); + + spin_unlock_bh(&mvmsta->lock); } if (PTR_ERR(sta) == -EBUSY || PTR_ERR(sta) == -ENOENT) { -- 2.20.1