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: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index d14c66d..5a6c36c 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -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)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index ac73b9c..0b50ae3 100644 (file)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -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;
+}
+
+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 (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;
+       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)

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 8a8e84b..5549ceb 100644 (file)
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -1,7 +1,7 @@
 /*
  * 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 */