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Commit 4f6b1b3d authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: fix last RX rate data consistency 



When storing the last_rate_* values in the RX code, there's nothing
to guarantee consistency, so a concurrent reader could see, e.g.
last_rate_idx on the new value, but last_rate_flag still on the old,
getting completely bogus values in the end.

To fix this, I lifted the sta_stats_encode_rate() function from my
old rate statistics code, which encodes the entire rate data into a
single 16-bit value, avoiding the consistency issue.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent b8da6b6a

net/mac80211/rx.c

+5 −16
Original line number Diff line number Diff line
@@ -1421,16 +1421,9 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx) 
		    test_sta_flag(sta, WLAN_STA_AUTHORIZED)) {

			sta->rx_stats.last_rx = jiffies;

			if (ieee80211_is_data(hdr->frame_control) &&

			    !is_multicast_ether_addr(hdr->addr1)) {

				sta->rx_stats.last_rate_idx =

					status->rate_idx;

				sta->rx_stats.last_rate_flag =

					status->flag;

				sta->rx_stats.last_rate_vht_flag =

					status->vht_flag;

				sta->rx_stats.last_rate_vht_nss =

					status->vht_nss;

			}

			    !is_multicast_ether_addr(hdr->addr1))

				sta->rx_stats.last_rate =

					sta_stats_encode_rate(status);

		}

	} else if (rx->sdata->vif.type == NL80211_IFTYPE_OCB) {

		sta->rx_stats.last_rx = jiffies;
@@ -1440,12 +1433,8 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx) 
		 * match the current local configuration when processed.

		 */

		sta->rx_stats.last_rx = jiffies;

		if (ieee80211_is_data(hdr->frame_control)) {

			sta->rx_stats.last_rate_idx = status->rate_idx;

			sta->rx_stats.last_rate_flag = status->flag;

			sta->rx_stats.last_rate_vht_flag = status->vht_flag;

			sta->rx_stats.last_rate_vht_nss = status->vht_nss;

		}

		if (ieee80211_is_data(hdr->frame_control))

			sta->rx_stats.last_rate = sta_stats_encode_rate(status);

	}



	if (rx->sdata->vif.type == NL80211_IFTYPE_STATION)

net/mac80211/sta_info.c

+32 −28
Original line number Diff line number Diff line
@@ -1928,43 +1928,47 @@ u8 sta_info_tx_streams(struct sta_info *sta) 
			>> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;

}



static void sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)

static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,

				  struct rate_info *rinfo)

{

	rinfo->flags = 0;



	if (sta->rx_stats.last_rate_flag & RX_FLAG_HT) {

		rinfo->flags |= RATE_INFO_FLAGS_MCS;

		rinfo->mcs = sta->rx_stats.last_rate_idx;

	} else if (sta->rx_stats.last_rate_flag & RX_FLAG_VHT) {

		rinfo->flags |= RATE_INFO_FLAGS_VHT_MCS;

		rinfo->nss = sta->rx_stats.last_rate_vht_nss;

		rinfo->mcs = sta->rx_stats.last_rate_idx;

	} else {

	rinfo->bw = (rate & STA_STATS_RATE_BW_MASK) >>

		STA_STATS_RATE_BW_SHIFT;



	if (rate & STA_STATS_RATE_VHT) {

		rinfo->flags = RATE_INFO_FLAGS_VHT_MCS;

		rinfo->mcs = rate & 0xf;

		rinfo->nss = (rate & 0xf0) >> 4;

	} else if (rate & STA_STATS_RATE_HT) {

		rinfo->flags = RATE_INFO_FLAGS_MCS;

		rinfo->mcs = rate & 0xff;

	} else if (rate & STA_STATS_RATE_LEGACY) {

		struct ieee80211_supported_band *sband;

		int shift = ieee80211_vif_get_shift(&sta->sdata->vif);

		u16 brate;



		sband = sta->local->hw.wiphy->bands[

				ieee80211_get_sdata_band(sta->sdata)];

		brate = sband->bitrates[sta->rx_stats.last_rate_idx].bitrate;

		unsigned int shift;



		sband = local->hw.wiphy->bands[(rate >> 4) & 0xf];

		brate = sband->bitrates[rate & 0xf].bitrate;

		if (rinfo->bw == RATE_INFO_BW_5)

			shift = 2;

		else if (rinfo->bw == RATE_INFO_BW_10)

			shift = 1;

		else

			shift = 0;

		rinfo->legacy = DIV_ROUND_UP(brate, 1 << shift);

	}



	if (sta->rx_stats.last_rate_flag & RX_FLAG_SHORT_GI)

	if (rate & STA_STATS_RATE_SGI)

		rinfo->flags |= RATE_INFO_FLAGS_SHORT_GI;

}



	if (sta->rx_stats.last_rate_flag & RX_FLAG_5MHZ)

		rinfo->bw = RATE_INFO_BW_5;

	else if (sta->rx_stats.last_rate_flag & RX_FLAG_10MHZ)

		rinfo->bw = RATE_INFO_BW_10;

	else if (sta->rx_stats.last_rate_flag & RX_FLAG_40MHZ)

		rinfo->bw = RATE_INFO_BW_40;

	else if (sta->rx_stats.last_rate_vht_flag & RX_VHT_FLAG_80MHZ)

		rinfo->bw = RATE_INFO_BW_80;

	else if (sta->rx_stats.last_rate_vht_flag & RX_VHT_FLAG_160MHZ)

		rinfo->bw = RATE_INFO_BW_160;

static void sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)

{

	u16 rate = ACCESS_ONCE(sta->rx_stats.last_rate);



	if (rate == STA_STATS_RATE_INVALID)

		rinfo->flags = 0;

	else

		rinfo->bw = RATE_INFO_BW_20;

		sta_stats_decode_rate(sta->local, rate, rinfo);

}



void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)

net/mac80211/sta_info.h

+40 −5
Original line number Diff line number Diff line 
/*

 * Copyright 2002-2005, Devicescape Software, Inc.

 * Copyright 2013-2014  Intel Mobile Communications GmbH

 * Copyright(c) 2015 Intel Deutschland GmbH

 * Copyright(c) 2015-2016 Intel Deutschland GmbH

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as
@@ -452,10 +452,7 @@ struct sta_info { 
		int last_signal;

		u8 chains;

		s8 chain_signal_last[IEEE80211_MAX_CHAINS];

		int last_rate_idx;

		u32 last_rate_flag;

		u32 last_rate_vht_flag;

		u8 last_rate_vht_nss;

		u16 last_rate;

		u64 msdu[IEEE80211_NUM_TIDS + 1];

	} rx_stats;

	struct {
@@ -683,4 +680,42 @@ void ieee80211_sta_ps_deliver_uapsd(struct sta_info *sta); 


unsigned long ieee80211_sta_last_active(struct sta_info *sta);



#define STA_STATS_RATE_INVALID		0

#define STA_STATS_RATE_VHT		0x8000

#define STA_STATS_RATE_HT		0x4000

#define STA_STATS_RATE_LEGACY		0x2000

#define STA_STATS_RATE_SGI		0x1000

#define STA_STATS_RATE_BW_SHIFT		9

#define STA_STATS_RATE_BW_MASK		(0x7 << STA_STATS_RATE_BW_SHIFT)



static inline u16 sta_stats_encode_rate(struct ieee80211_rx_status *s)

{

	u16 r = s->rate_idx;



	if (s->vht_flag & RX_VHT_FLAG_80MHZ)

		r |= RATE_INFO_BW_80 << STA_STATS_RATE_BW_SHIFT;

	else if (s->vht_flag & RX_VHT_FLAG_160MHZ)

		r |= RATE_INFO_BW_160 << STA_STATS_RATE_BW_SHIFT;

	else if (s->flag & RX_FLAG_40MHZ)

		r |= RATE_INFO_BW_40 << STA_STATS_RATE_BW_SHIFT;

	else if (s->flag & RX_FLAG_10MHZ)

		r |= RATE_INFO_BW_10 << STA_STATS_RATE_BW_SHIFT;

	else if (s->flag & RX_FLAG_5MHZ)

		r |= RATE_INFO_BW_5 << STA_STATS_RATE_BW_SHIFT;

	else

		r |= RATE_INFO_BW_20 << STA_STATS_RATE_BW_SHIFT;



	if (s->flag & RX_FLAG_SHORT_GI)

		r |= STA_STATS_RATE_SGI;



	if (s->flag & RX_FLAG_VHT)

		r |= STA_STATS_RATE_VHT | (s->vht_nss << 4);

	else if (s->flag & RX_FLAG_HT)

		r |= STA_STATS_RATE_HT;

	else

		r |= STA_STATS_RATE_LEGACY | (s->band << 4);



	return r;

}



#endif /* STA_INFO_H */