mac80211: enable collecting station statistics per-CPU

If the driver advertises the new HW flag USE_RSS, make the
station statistics on the fast-rx path per-CPU. This will
enable calling the RX in parallel, only hitting locking or
shared cachelines when the fast-RX path isn't available.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

5 files changed, 142 insertions, 46 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index fd5ec446a7a9..5f4b4c773a92 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1980,6 +1980,9 @@ struct ieee80211_txq {
  *      order and does not need to manage its own reorder buffer or BA session
  *      timeout.
  *
+ * @IEEE80211_HW_USES_RSS: The device uses RSS and thus requires parallel RX,
+ *      which implies using per-CPU station statistics.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -2017,6 +2020,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_BEACON_TX_STATUS,
         IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR,
         IEEE80211_HW_SUPPORTS_REORDERING_BUFFER,
+        IEEE80211_HW_USES_RSS,
 
         /* keep last, obviously */
         NUM_IEEE80211_HW_FLAGS
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 4ab5c522ceee..52ed2afc408d 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -127,6 +127,7 @@ static const char *hw_flag_names[] = {
         FLAG(BEACON_TX_STATUS),
         FLAG(NEEDS_UNIQUE_STA_ADDR),
         FLAG(SUPPORTS_REORDERING_BUFFER),
+        FLAG(USES_RSS),
 #undef FLAG
 };
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 96f8bbf21649..c2b659e9a9f9 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3528,6 +3528,8 @@ void ieee80211_check_fast_rx(struct sta_info *sta)
         ether_addr_copy(fastrx.rfc1042_hdr, rfc1042_header);
         ether_addr_copy(fastrx.vif_addr, sdata->vif.addr);
 
+        fastrx.uses_rss = ieee80211_hw_check(&local->hw, USES_RSS);
+
         /* fast-rx doesn't do reordering */
         if (ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) &&
             !ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER))
@@ -3678,6 +3680,10 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx,
                 u8 da[ETH_ALEN];
                 u8 sa[ETH_ALEN];
         } addrs __aligned(2);
+        struct ieee80211_sta_rx_stats *stats = &sta->rx_stats;
+
+        if (fast_rx->uses_rss)
+                stats = this_cpu_ptr(sta->pcpu_rx_stats);
 
         /* for parallel-rx, we need to have DUP_VALIDATED, otherwise we write
          * to a common data structure; drivers can implement that per queue
@@ -3759,29 +3765,32 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx,
         }
 
         /* statistics part of ieee80211_rx_h_sta_process() */
-        sta->rx_stats.last_rx = jiffies;
-        sta->rx_stats.last_rate = sta_stats_encode_rate(status);
+        stats->last_rx = jiffies;
+        stats->last_rate = sta_stats_encode_rate(status);
 
-        sta->rx_stats.fragments++;
+        stats->fragments++;
 
         if (!(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
-                sta->rx_stats.last_signal = status->signal;
-                ewma_signal_add(&sta->rx_stats_avg.signal, -status->signal);
+                stats->last_signal = status->signal;
+                if (!fast_rx->uses_rss)
+                        ewma_signal_add(&sta->rx_stats_avg.signal,
+                                        -status->signal);
         }
 
         if (status->chains) {
                 int i;
 
-                sta->rx_stats.chains = status->chains;
+                stats->chains = status->chains;
                 for (i = 0; i < ARRAY_SIZE(status->chain_signal); i++) {
                         int signal = status->chain_signal[i];
 
                         if (!(status->chains & BIT(i)))
                                 continue;
 
-                        sta->rx_stats.chain_signal_last[i] = signal;
-                        ewma_signal_add(&sta->rx_stats_avg.chain_signal[i],
-                                        -signal);
+                        stats->chain_signal_last[i] = signal;
+                        if (!fast_rx->uses_rss)
+                                ewma_signal_add(&sta->rx_stats_avg.chain_signal[i],
+                                                -signal);
                 }
         }
         /* end of statistics */
@@ -3806,10 +3815,10 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx,
          * for non-QoS-data frames. Here we know it's a data
          * frame, so count MSDUs.
          */
-        u64_stats_update_begin(&sta->rx_stats.syncp);
-        sta->rx_stats.msdu[rx->seqno_idx]++;
-        sta->rx_stats.bytes += orig_len;
-        u64_stats_update_end(&sta->rx_stats.syncp);
+        u64_stats_update_begin(&stats->syncp);
+        stats->msdu[rx->seqno_idx]++;
+        stats->bytes += orig_len;
+        u64_stats_update_end(&stats->syncp);
 
         if (fast_rx->internal_forward) {
                 struct sta_info *dsta = sta_info_get(rx->sdata, skb->data);
@@ -3840,7 +3849,7 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx,
         return true;
  drop:
         dev_kfree_skb(skb);
-        sta->rx_stats.dropped++;
+        stats->dropped++;
         return true;
 }
 
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index a0ce7e40f420..cf2aca0cc200 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -254,6 +254,7 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 #ifdef CONFIG_MAC80211_MESH
         kfree(sta->mesh);
 #endif
+        free_percpu(sta->pcpu_rx_stats);
         kfree(sta);
 }
 
@@ -311,6 +312,13 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
         if (!sta)
                 return NULL;
 
+        if (ieee80211_hw_check(hw, USES_RSS)) {
+                sta->pcpu_rx_stats =
+                        alloc_percpu(struct ieee80211_sta_rx_stats);
+                if (!sta->pcpu_rx_stats)
+                        goto free;
+        }
+
         spin_lock_init(&sta->lock);
         spin_lock_init(&sta->ps_lock);
         INIT_WORK(&sta->drv_deliver_wk, sta_deliver_ps_frames);
@@ -1932,6 +1940,28 @@ u8 sta_info_tx_streams(struct sta_info *sta)
                         >> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;
 }
 
+static struct ieee80211_sta_rx_stats *
+sta_get_last_rx_stats(struct sta_info *sta)
+{
+        struct ieee80211_sta_rx_stats *stats = &sta->rx_stats;
+        struct ieee80211_local *local = sta->local;
+        int cpu;
+
+        if (!ieee80211_hw_check(&local->hw, USES_RSS))
+                return stats;
+
+        for_each_possible_cpu(cpu) {
+                struct ieee80211_sta_rx_stats *cpustats;
+
+                cpustats = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+
+                if (time_after(cpustats->last_rx, stats->last_rx))
+                        stats = cpustats;
+        }
+
+        return stats;
+}
+
 static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,
                                   struct rate_info *rinfo)
 {
@@ -1967,7 +1997,7 @@ static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,
 
 static void sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)
 {
-        u16 rate = ACCESS_ONCE(sta->rx_stats.last_rate);
+        u16 rate = ACCESS_ONCE(sta_get_last_rx_stats(sta)->last_rate);
 
         if (rate == STA_STATS_RATE_INVALID)
                 rinfo->flags = 0;
@@ -2010,13 +2040,29 @@ static void sta_set_tidstats(struct sta_info *sta,
         }
 }
 
+static inline u64 sta_get_stats_bytes(struct ieee80211_sta_rx_stats *rxstats)
+{
+        unsigned int start;
+        u64 value;
+
+        do {
+                start = u64_stats_fetch_begin(&rxstats->syncp);
+                value = rxstats->bytes;
+        } while (u64_stats_fetch_retry(&rxstats->syncp, start));
+
+        return value;
+}
+
 void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 {
         struct ieee80211_sub_if_data *sdata = sta->sdata;
         struct ieee80211_local *local = sdata->local;
         struct rate_control_ref *ref = NULL;
         u32 thr = 0;
-        int i, ac;
+        int i, ac, cpu;
+        struct ieee80211_sta_rx_stats *last_rxstats;
+
+        last_rxstats = sta_get_last_rx_stats(sta);
 
         if (test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
                 ref = local->rate_ctrl;
@@ -2064,17 +2110,30 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 
         if (!(sinfo->filled & (BIT(NL80211_STA_INFO_RX_BYTES64) |
                                BIT(NL80211_STA_INFO_RX_BYTES)))) {
-                unsigned int start;
+                sinfo->rx_bytes += sta_get_stats_bytes(&sta->rx_stats);
+
+                if (sta->pcpu_rx_stats) {
+                        for_each_possible_cpu(cpu) {
+                                struct ieee80211_sta_rx_stats *cpurxs;
+
+                                cpurxs = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+                                sinfo->rx_bytes += sta_get_stats_bytes(cpurxs);
+                        }
+                }
 
-                do {
-                        start = u64_stats_fetch_begin(&sta->rx_stats.syncp);
-                        sinfo->rx_bytes = sta->rx_stats.bytes;
-                } while (u64_stats_fetch_retry(&sta->rx_stats.syncp, start));
                 sinfo->filled |= BIT(NL80211_STA_INFO_RX_BYTES64);
         }
 
         if (!(sinfo->filled & BIT(NL80211_STA_INFO_RX_PACKETS))) {
                 sinfo->rx_packets = sta->rx_stats.packets;
+                if (sta->pcpu_rx_stats) {
+                        for_each_possible_cpu(cpu) {
+                                struct ieee80211_sta_rx_stats *cpurxs;
+
+                                cpurxs = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+                                sinfo->rx_packets += cpurxs->packets;
+                        }
+                }
                 sinfo->filled |= BIT(NL80211_STA_INFO_RX_PACKETS);
         }
 
@@ -2089,6 +2148,14 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
         }
 
         sinfo->rx_dropped_misc = sta->rx_stats.dropped;
+        if (sta->pcpu_rx_stats) {
+                for_each_possible_cpu(cpu) {
+                        struct ieee80211_sta_rx_stats *cpurxs;
+
+                        cpurxs = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+                        sinfo->rx_packets += cpurxs->dropped;
+                }
+        }
 
         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
             !(sdata->vif.driver_flags & IEEE80211_VIF_BEACON_FILTER)) {
@@ -2100,27 +2167,34 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
         if (ieee80211_hw_check(&sta->local->hw, SIGNAL_DBM) ||
             ieee80211_hw_check(&sta->local->hw, SIGNAL_UNSPEC)) {
                 if (!(sinfo->filled & BIT(NL80211_STA_INFO_SIGNAL))) {
-                        sinfo->signal = (s8)sta->rx_stats.last_signal;
+                        sinfo->signal = (s8)last_rxstats->last_signal;
                         sinfo->filled |= BIT(NL80211_STA_INFO_SIGNAL);
                 }
 
-                if (!(sinfo->filled & BIT(NL80211_STA_INFO_SIGNAL_AVG))) {
+                if (!sta->pcpu_rx_stats &&
+                    !(sinfo->filled & BIT(NL80211_STA_INFO_SIGNAL_AVG))) {
                         sinfo->signal_avg =
                                 -ewma_signal_read(&sta->rx_stats_avg.signal);
                         sinfo->filled |= BIT(NL80211_STA_INFO_SIGNAL_AVG);
                 }
         }
 
-        if (sta->rx_stats.chains &&
+        /* for the average - if pcpu_rx_stats isn't set - rxstats must point to
+         * the sta->rx_stats struct, so the check here is fine with and without
+         * pcpu statistics
+         */
+        if (last_rxstats->chains &&
             !(sinfo->filled & (BIT(NL80211_STA_INFO_CHAIN_SIGNAL) |
                                BIT(NL80211_STA_INFO_CHAIN_SIGNAL_AVG)))) {
-                sinfo->filled |= BIT(NL80211_STA_INFO_CHAIN_SIGNAL) |
-                                 BIT(NL80211_STA_INFO_CHAIN_SIGNAL_AVG);
+                sinfo->filled |= BIT(NL80211_STA_INFO_CHAIN_SIGNAL);
+                if (!sta->pcpu_rx_stats)
+                        sinfo->filled |= BIT(NL80211_STA_INFO_CHAIN_SIGNAL_AVG);
+
+                sinfo->chains = last_rxstats->chains;
 
-                sinfo->chains = sta->rx_stats.chains;
                 for (i = 0; i < ARRAY_SIZE(sinfo->chain_signal); i++) {
                         sinfo->chain_signal[i] =
-                                sta->rx_stats.chain_signal_last[i];
+                                last_rxstats->chain_signal_last[i];
                         sinfo->chain_signal_avg[i] =
                                 -ewma_signal_read(&sta->rx_stats_avg.chain_signal[i]);
                 }
@@ -2213,7 +2287,9 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 
 unsigned long ieee80211_sta_last_active(struct sta_info *sta)
 {
-        if (time_after(sta->rx_stats.last_rx, sta->status_stats.last_ack))
-                return sta->rx_stats.last_rx;
+        struct ieee80211_sta_rx_stats *stats = sta_get_last_rx_stats(sta);
+
+        if (time_after(stats->last_rx, sta->status_stats.last_ack))
+                return stats->last_rx;
         return sta->status_stats.last_ack;
 }
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index a0a06609338d..dd6c6d400208 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -297,6 +297,7 @@ struct ieee80211_fast_tx {
  * @key: bool indicating encryption is expected (key is set)
  * @sta_notify: notify the MLME code (once)
  * @internal_forward: forward froms internally on AP/VLAN type interfaces
+ * @uses_rss: copy of USES_RSS hw flag
  * @da_offs: offset of the DA in the header (for header conversion)
  * @sa_offs: offset of the SA in the header (for header conversion)
  * @rcu_head: RCU head for freeing this structure
@@ -311,7 +312,8 @@ struct ieee80211_fast_rx {
         u8 icv_len;
         u8 key:1,
            sta_notify:1,
-           internal_forward:1;
+           internal_forward:1,
+           uses_rss:1;
         u8 da_offs, sa_offs;
 
         struct rcu_head rcu_head;
@@ -367,6 +369,21 @@ struct mesh_sta {
 
 DECLARE_EWMA(signal, 1024, 8)
 
+struct ieee80211_sta_rx_stats {
+        unsigned long packets;
+        unsigned long last_rx;
+        unsigned long num_duplicates;
+        unsigned long fragments;
+        unsigned long dropped;
+        int last_signal;
+        u8 chains;
+        s8 chain_signal_last[IEEE80211_MAX_CHAINS];
+        u16 last_rate;
+        struct u64_stats_sync syncp;
+        u64 bytes;
+        u64 msdu[IEEE80211_NUM_TIDS + 1];
+};
+
 /**
  * struct sta_info - STA information
  *
@@ -428,6 +445,8 @@ DECLARE_EWMA(signal, 1024, 8)
  *      the BSS one.
  * @tx_stats: TX statistics
  * @rx_stats: RX statistics
+ * @pcpu_rx_stats: per-CPU RX statistics, assigned only if the driver needs
+ *      this (by advertising the USES_RSS hw flag)
  * @status_stats: TX status statistics
  */
 struct sta_info {
@@ -448,6 +467,7 @@ struct sta_info {
 
         struct ieee80211_fast_tx __rcu *fast_tx;
         struct ieee80211_fast_rx __rcu *fast_rx;
+        struct ieee80211_sta_rx_stats __percpu *pcpu_rx_stats;
 
 #ifdef CONFIG_MAC80211_MESH
         struct mesh_sta *mesh;
@@ -477,21 +497,7 @@ struct sta_info {
         long last_connected;
 
         /* Updated from RX path only, no locking requirements */
-        struct {
-                unsigned long packets;
-                unsigned long last_rx;
-                unsigned long num_duplicates;
-                unsigned long fragments;
-                unsigned long dropped;
-                int last_signal;
-                u8 chains;
-                s8 chain_signal_last[IEEE80211_MAX_CHAINS];
-                u16 last_rate;
-
-                struct u64_stats_sync syncp;
-                u64 bytes;
-                u64 msdu[IEEE80211_NUM_TIDS + 1];
-        } rx_stats;
+        struct ieee80211_sta_rx_stats rx_stats;
         struct {
                 struct ewma_signal signal;
                 struct ewma_signal chain_signal[IEEE80211_MAX_CHAINS];