mac80211: rework TX filtered frame code (d46e144b) · Commits · e / devices / android_kernel_teracube_2e

include/net/mac80211.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -228,7 +228,8 @@ struct ieee80211_tx_control {
		#define IEEE80211_TXCTL_NO_ACK (1<<4) /* tell the low level not to
		* wait for an ack */
		#define IEEE80211_TXCTL_RATE_CTRL_PROBE (1<<5)
		#define IEEE80211_TXCTL_CLEAR_DST_MASK (1<<6)
		#define IEEE80211_TXCTL_CLEAR_PS_FILT (1<<6) /* clear powersave filter
		* for destination station */
		#define IEEE80211_TXCTL_REQUEUE (1<<7)
		#define IEEE80211_TXCTL_FIRST_FRAGMENT (1<<8) /* this is a first fragment of
		* the frame */

net/mac80211/ieee80211.c

+79 −42

Original line number	Diff line number	Diff line
		@@ -1178,6 +1178,77 @@ static void ieee80211_remove_tx_extra(struct ieee80211_local *local,
		}
		}

		static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
		struct sta_info *sta,
		struct sk_buff *skb,
		struct ieee80211_tx_status *status)
		{
		sta->tx_filtered_count++;

		/*
		* Clear the TX filter mask for this STA when sending the next
		* packet. If the STA went to power save mode, this will happen
		* happen when it wakes up for the next time.
		*/
		sta->flags \|= WLAN_STA_CLEAR_PS_FILT;

		/*
		* This code races in the following way:
		*
		* (1) STA sends frame indicating it will go to sleep and does so
		* (2) hardware/firmware adds STA to filter list, passes frame up
		* (3) hardware/firmware processes TX fifo and suppresses a frame
		* (4) we get TX status before having processed the frame and
		* knowing that the STA has gone to sleep.
		*
		* This is actually quite unlikely even when both those events are
		* processed from interrupts coming in quickly after one another or
		* even at the same time because we queue both TX status events and
		* RX frames to be processed by a tasklet and process them in the
		* same order that they were received or TX status last. Hence, there
		* is no race as long as the frame RX is processed before the next TX
		* status, which drivers can ensure, see below.
		*
		* Note that this can only happen if the hardware or firmware can
		* actually add STAs to the filter list, if this is done by the
		* driver in response to set_tim() (which will only reduce the race
		* this whole filtering tries to solve, not completely solve it)
		* this situation cannot happen.
		*
		* To completely solve this race drivers need to make sure that they
		* (a) don't mix the irq-safe/not irq-safe TX status/RX processing
		* functions and
		* (b) always process RX events before TX status events if ordering
		* can be unknown, for example with different interrupt status
		* bits.
		*/
		if (sta->flags & WLAN_STA_PS &&
		skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
		ieee80211_remove_tx_extra(local, sta->key, skb,
		&status->control);
		skb_queue_tail(&sta->tx_filtered, skb);
		return;
		}

		if (!(sta->flags & WLAN_STA_PS) &&
		!(status->control.flags & IEEE80211_TXCTL_REQUEUE)) {
		/* Software retry the packet once */
		status->control.flags \|= IEEE80211_TXCTL_REQUEUE;
		ieee80211_remove_tx_extra(local, sta->key, skb,
		&status->control);
		dev_queue_xmit(skb);
		return;
		}

		if (net_ratelimit())
		printk(KERN_DEBUG "%s: dropped TX filtered frame, "
		"queue_len=%d PS=%d @%lu\n",
		wiphy_name(local->hw.wiphy),
		skb_queue_len(&sta->tx_filtered),
		!!(sta->flags & WLAN_STA_PS), jiffies);
		dev_kfree_skb(skb);
		}

		void ieee80211_tx_status(struct ieee80211_hw hw, struct sk_buff skb,
		struct ieee80211_tx_status *status)
		{
		@@ -1202,11 +1273,16 @@ void ieee80211_tx_status(struct ieee80211_hw hw, struct sk_buff skb,
		sta = sta_info_get(local, hdr->addr1);
		if (sta) {
		if (sta->flags & WLAN_STA_PS) {
		/* The STA is in power save mode, so assume
		/*
		* The STA is in power save mode, so assume
		* that this TX packet failed because of that.
		*/
		status->excessive_retries = 0;
		status->flags \|= IEEE80211_TX_STATUS_TX_FILTERED;
		ieee80211_handle_filtered_frame(local, sta,
		skb, status);
		sta_info_put(sta);
		return;
		}
		sta_info_put(sta);
		}
		@@ -1216,47 +1292,8 @@ void ieee80211_tx_status(struct ieee80211_hw hw, struct sk_buff skb,
		struct sta_info *sta;
		sta = sta_info_get(local, hdr->addr1);
		if (sta) {
		sta->tx_filtered_count++;

		/* Clear the TX filter mask for this STA when sending
		* the next packet. If the STA went to power save mode,
		* this will happen when it is waking up for the next
		* time. */
		sta->clear_dst_mask = 1;

		/* TODO: Is the WLAN_STA_PS flag always set here or is
		* the race between RX and TX status causing some
		* packets to be filtered out before 80211.o gets an
		* update for PS status? This seems to be the case, so
		* no changes are likely to be needed. */
		if (sta->flags & WLAN_STA_PS &&
		skb_queue_len(&sta->tx_filtered) <
		STA_MAX_TX_BUFFER) {
		ieee80211_remove_tx_extra(local, sta->key,
		skb,
		&status->control);
		skb_queue_tail(&sta->tx_filtered, skb);
		} else if (!(sta->flags & WLAN_STA_PS) &&
		!(status->control.flags & IEEE80211_TXCTL_REQUEUE)) {
		/* Software retry the packet once */
		status->control.flags \|= IEEE80211_TXCTL_REQUEUE;
		ieee80211_remove_tx_extra(local, sta->key,
		skb,
		&status->control);
		dev_queue_xmit(skb);
		} else {
		if (net_ratelimit()) {
		printk(KERN_DEBUG "%s: dropped TX "
		"filtered frame queue_len=%d "
		"PS=%d @%lu\n",
		wiphy_name(local->hw.wiphy),
		skb_queue_len(
		&sta->tx_filtered),
		!!(sta->flags & WLAN_STA_PS),
		jiffies);
		}
		dev_kfree_skb(skb);
		}
		ieee80211_handle_filtered_frame(local, sta, skb,
		status);
		sta_info_put(sta);
		return;
		}

net/mac80211/sta_info.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -32,6 +32,9 @@
		* @WLAN_STA_WME: Station is a QoS-STA.
		* @WLAN_STA_WDS: Station is one of our WDS peers.
		* @WLAN_STA_PSPOLL: Station has just PS-polled us.
		* @WLAN_STA_CLEAR_PS_FILT: Clear PS filter in hardware (using the
		* IEEE80211_TXCTL_CLEAR_PS_FILT control flag) when the next
		* frame to this station is transmitted.
		*/
		enum ieee80211_sta_info_flags {
		WLAN_STA_AUTH = 1<<0,
		@@ -43,6 +46,7 @@ enum ieee80211_sta_info_flags {
		WLAN_STA_WME = 1<<6,
		WLAN_STA_WDS = 1<<7,
		WLAN_STA_PSPOLL = 1<<8,
		WLAN_STA_CLEAR_PS_FILT = 1<<9,
		};

		#define STA_TID_NUM 16
		@@ -136,8 +140,6 @@ struct sta_info {
		struct sk_buff_head tx_filtered; /* buffer of TX frames that were
		* already given to low-level driver,
		* but were filtered */
		int clear_dst_mask;

		unsigned long rx_packets, tx_packets; /* number of RX/TX MSDUs */
		unsigned long rx_bytes, tx_bytes;
		unsigned long tx_retry_failed, tx_retry_count;

net/mac80211/tx.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -1020,10 +1020,10 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
		}

		if (!tx->sta)
		control->flags \|= IEEE80211_TXCTL_CLEAR_DST_MASK;
		else if (tx->sta->clear_dst_mask) {
		control->flags \|= IEEE80211_TXCTL_CLEAR_DST_MASK;
		tx->sta->clear_dst_mask = 0;
		control->flags \|= IEEE80211_TXCTL_CLEAR_PS_FILT;
		else if (tx->sta->flags & WLAN_STA_CLEAR_PS_FILT) {
		control->flags \|= IEEE80211_TXCTL_CLEAR_PS_FILT;
		tx->sta->flags &= ~WLAN_STA_CLEAR_PS_FILT;
		}

		hdrlen = ieee80211_get_hdrlen(tx->fc);
		@@ -1084,7 +1084,7 @@ static int __ieee80211_tx(struct ieee80211_local local, struct sk_buff skb,
		if (tx->u.tx.extra_frag) {
		control->flags &= ~(IEEE80211_TXCTL_USE_RTS_CTS \|
		IEEE80211_TXCTL_USE_CTS_PROTECT \|
		IEEE80211_TXCTL_CLEAR_DST_MASK \|
		IEEE80211_TXCTL_CLEAR_PS_FILT \|
		IEEE80211_TXCTL_FIRST_FRAGMENT);
		for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
		if (!tx->u.tx.extra_frag[i])
		@@ -1806,7 +1806,7 @@ struct sk_buff ieee80211_beacon_get(struct ieee80211_hw hw,
		control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
		control->flags \|= IEEE80211_TXCTL_NO_ACK;
		control->retry_limit = 1;
		control->flags \|= IEEE80211_TXCTL_CLEAR_DST_MASK;
		control->flags \|= IEEE80211_TXCTL_CLEAR_PS_FILT;
		}

		ap->num_beacons++;