--- /dev/null
+From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
+Date: Thu, 12 Dec 2019 12:14:37 +0100
+Subject: [PATCH] mac80211: Turn AQL into an NL80211_EXT_FEATURE
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Instead of just having an airtime flag in debugfs, turn AQL into a proper
+NL80211_EXT_FEATURE, so drivers can turn it on when they are ready, and so
+we also expose the presence of the feature to userspace.
+
+This also has the effect of flipping the default, so drivers have to opt in
+to using AQL instead of getting it by default with TXQs. To keep
+functionality the same as pre-patch, we set this feature for ath10k (which
+is where it is needed the most).
+
+While we're at it, split out the debugfs interface so AQL gets its own
+per-station debugfs file instead of using the 'airtime' file.
+
+[Johannes:]
+This effectively disables AQL for iwlwifi, where it fixes a number of
+issues:
+ * TSO in iwlwifi is causing underflows and associated warnings in AQL
+ * HE (802.11ax) rates aren't reported properly so at HE rates, AQL could
+ never have a valid estimate (it'd use 6 Mbps instead of up to 2400!)
+
+Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Link: https://lore.kernel.org/r/20191212111437.224294-1-toke@redhat.com
+Fixes: 3ace10f5b5ad ("mac80211: Implement Airtime-based Queue Limit (AQL)")
+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
+---
+
+--- a/drivers/net/wireless/ath/ath10k/mac.c
++++ b/drivers/net/wireless/ath/ath10k/mac.c
+@@ -8868,6 +8868,7 @@ int ath10k_mac_register(struct ath10k *a
+ wiphy_ext_feature_set(ar->hw->wiphy, NL80211_EXT_FEATURE_VHT_IBSS);
+ wiphy_ext_feature_set(ar->hw->wiphy,
+ NL80211_EXT_FEATURE_SET_SCAN_DWELL);
++ wiphy_ext_feature_set(ar->hw->wiphy, NL80211_EXT_FEATURE_AQL);
+
+ if (test_bit(WMI_SERVICE_TX_DATA_ACK_RSSI, ar->wmi.svc_map) ||
+ test_bit(WMI_SERVICE_HTT_MGMT_TX_COMP_VALID_FLAGS, ar->wmi.svc_map))
+--- a/include/uapi/linux/nl80211.h
++++ b/include/uapi/linux/nl80211.h
+@@ -5484,6 +5484,10 @@ enum nl80211_feature_flags {
+ * @NL80211_EXT_FEATURE_SAE_OFFLOAD: Device wants to do SAE authentication in
+ * station mode (SAE password is passed as part of the connect command).
+ *
++ * @NL80211_EXT_FEATURE_AQL: The driver supports the Airtime Queue Limit (AQL)
++ * feature, which prevents bufferbloat by using the expected transmission
++ * time to limit the amount of data buffered in the hardware.
++ *
+ * @NUM_NL80211_EXT_FEATURES: number of extended features.
+ * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
+ */
+@@ -5529,6 +5533,8 @@ enum nl80211_ext_feature_index {
+ NL80211_EXT_FEATURE_EXT_KEY_ID,
+ NL80211_EXT_FEATURE_STA_TX_PWR,
+ NL80211_EXT_FEATURE_SAE_OFFLOAD,
++ NL80211_EXT_FEATURE_VLAN_OFFLOAD,
++ NL80211_EXT_FEATURE_AQL,
+
+ /* add new features before the definition below */
+ NUM_NL80211_EXT_FEATURES,
+--- a/net/mac80211/debugfs_sta.c
++++ b/net/mac80211/debugfs_sta.c
+@@ -201,8 +201,6 @@ static ssize_t sta_airtime_read(struct f
+ char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf;
+ u64 rx_airtime = 0, tx_airtime = 0;
+ s64 deficit[IEEE80211_NUM_ACS];
+- u32 q_depth[IEEE80211_NUM_ACS];
+- u32 q_limit_l[IEEE80211_NUM_ACS], q_limit_h[IEEE80211_NUM_ACS];
+ ssize_t rv;
+ int ac;
+
+@@ -214,6 +212,56 @@ static ssize_t sta_airtime_read(struct f
+ rx_airtime += sta->airtime[ac].rx_airtime;
+ tx_airtime += sta->airtime[ac].tx_airtime;
+ deficit[ac] = sta->airtime[ac].deficit;
++ spin_unlock_bh(&local->active_txq_lock[ac]);
++ }
++
++ p += scnprintf(p, bufsz + buf - p,
++ "RX: %llu us\nTX: %llu us\nWeight: %u\n"
++ "Deficit: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n",
++ rx_airtime, tx_airtime, sta->airtime_weight,
++ deficit[0], deficit[1], deficit[2], deficit[3]);
++
++ rv = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
++ kfree(buf);
++ return rv;
++}
++
++static ssize_t sta_airtime_write(struct file *file, const char __user *userbuf,
++ size_t count, loff_t *ppos)
++{
++ struct sta_info *sta = file->private_data;
++ struct ieee80211_local *local = sta->sdata->local;
++ int ac;
++
++ for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
++ spin_lock_bh(&local->active_txq_lock[ac]);
++ sta->airtime[ac].rx_airtime = 0;
++ sta->airtime[ac].tx_airtime = 0;
++ sta->airtime[ac].deficit = sta->airtime_weight;
++ spin_unlock_bh(&local->active_txq_lock[ac]);
++ }
++
++ return count;
++}
++STA_OPS_RW(airtime);
++
++static ssize_t sta_aql_read(struct file *file, char __user *userbuf,
++ size_t count, loff_t *ppos)
++{
++ struct sta_info *sta = file->private_data;
++ struct ieee80211_local *local = sta->sdata->local;
++ size_t bufsz = 400;
++ char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf;
++ u32 q_depth[IEEE80211_NUM_ACS];
++ u32 q_limit_l[IEEE80211_NUM_ACS], q_limit_h[IEEE80211_NUM_ACS];
++ ssize_t rv;
++ int ac;
++
++ if (!buf)
++ return -ENOMEM;
++
++ for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
++ spin_lock_bh(&local->active_txq_lock[ac]);
+ q_limit_l[ac] = sta->airtime[ac].aql_limit_low;
+ q_limit_h[ac] = sta->airtime[ac].aql_limit_high;
+ spin_unlock_bh(&local->active_txq_lock[ac]);
+@@ -221,12 +269,8 @@ static ssize_t sta_airtime_read(struct f
+ }
+
+ p += scnprintf(p, bufsz + buf - p,
+- "RX: %llu us\nTX: %llu us\nWeight: %u\n"
+- "Deficit: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n"
+ "Q depth: VO: %u us VI: %u us BE: %u us BK: %u us\n"
+ "Q limit[low/high]: VO: %u/%u VI: %u/%u BE: %u/%u BK: %u/%u\n",
+- rx_airtime, tx_airtime, sta->airtime_weight,
+- deficit[0], deficit[1], deficit[2], deficit[3],
+ q_depth[0], q_depth[1], q_depth[2], q_depth[3],
+ q_limit_l[0], q_limit_h[0], q_limit_l[1], q_limit_h[1],
+ q_limit_l[2], q_limit_h[2], q_limit_l[3], q_limit_h[3]),
+@@ -236,11 +280,10 @@ static ssize_t sta_airtime_read(struct f
+ return rv;
+ }
+
+-static ssize_t sta_airtime_write(struct file *file, const char __user *userbuf,
++static ssize_t sta_aql_write(struct file *file, const char __user *userbuf,
+ size_t count, loff_t *ppos)
+ {
+ struct sta_info *sta = file->private_data;
+- struct ieee80211_local *local = sta->sdata->local;
+ u32 ac, q_limit_l, q_limit_h;
+ char _buf[100] = {}, *buf = _buf;
+
+@@ -251,7 +294,7 @@ static ssize_t sta_airtime_write(struct
+ return -EFAULT;
+
+ buf[sizeof(_buf) - 1] = '\0';
+- if (sscanf(buf, "queue limit %u %u %u", &ac, &q_limit_l, &q_limit_h)
++ if (sscanf(buf, "limit %u %u %u", &ac, &q_limit_l, &q_limit_h)
+ != 3)
+ return -EINVAL;
+
+@@ -261,17 +304,10 @@ static ssize_t sta_airtime_write(struct
+ sta->airtime[ac].aql_limit_low = q_limit_l;
+ sta->airtime[ac].aql_limit_high = q_limit_h;
+
+- for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
+- spin_lock_bh(&local->active_txq_lock[ac]);
+- sta->airtime[ac].rx_airtime = 0;
+- sta->airtime[ac].tx_airtime = 0;
+- sta->airtime[ac].deficit = sta->airtime_weight;
+- spin_unlock_bh(&local->active_txq_lock[ac]);
+- }
+-
+ return count;
+ }
+-STA_OPS_RW(airtime);
++STA_OPS_RW(aql);
++
+
+ static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf,
+ size_t count, loff_t *ppos)
+@@ -1001,6 +1037,10 @@ void ieee80211_sta_debugfs_add(struct st
+ NL80211_EXT_FEATURE_AIRTIME_FAIRNESS))
+ DEBUGFS_ADD(airtime);
+
++ if (wiphy_ext_feature_isset(local->hw.wiphy,
++ NL80211_EXT_FEATURE_AQL))
++ DEBUGFS_ADD(aql);
++
+ if (sizeof(sta->driver_buffered_tids) == sizeof(u32))
+ debugfs_create_x32("driver_buffered_tids", 0400,
+ sta->debugfs_dir,
+--- a/net/mac80211/main.c
++++ b/net/mac80211/main.c
+@@ -674,9 +674,7 @@ struct ieee80211_hw *ieee80211_alloc_hw_
+ IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H;
+ }
+
+- local->airtime_flags = AIRTIME_USE_TX |
+- AIRTIME_USE_RX |
+- AIRTIME_USE_AQL;
++ local->airtime_flags = AIRTIME_USE_TX | AIRTIME_USE_RX;
+ local->aql_threshold = IEEE80211_AQL_THRESHOLD;
+ atomic_set(&local->aql_total_pending_airtime, 0);
+
+--- a/net/mac80211/sta_info.c
++++ b/net/mac80211/sta_info.c
+@@ -1917,6 +1917,9 @@ void ieee80211_sta_update_pending_airtim
+ {
+ int tx_pending;
+
++ if (!wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))
++ return;
++
+ if (!tx_completed) {
+ if (sta)
+ atomic_add(tx_airtime,
+--- a/net/mac80211/sta_info.h
++++ b/net/mac80211/sta_info.h
+@@ -127,7 +127,6 @@ enum ieee80211_agg_stop_reason {
+ /* Debugfs flags to enable/disable use of RX/TX airtime in scheduler */
+ #define AIRTIME_USE_TX BIT(0)
+ #define AIRTIME_USE_RX BIT(1)
+-#define AIRTIME_USE_AQL BIT(2)
+
+ struct airtime_info {
+ u64 rx_airtime;
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -3658,7 +3658,7 @@ begin:
+
+ IEEE80211_SKB_CB(skb)->control.vif = vif;
+
+- if (local->airtime_flags & AIRTIME_USE_AQL) {
++ if (wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
+ u32 airtime;
+
+ airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
+@@ -3780,7 +3780,7 @@ bool ieee80211_txq_airtime_check(struct
+ struct sta_info *sta;
+ struct ieee80211_local *local = hw_to_local(hw);
+
+- if (!(local->airtime_flags & AIRTIME_USE_AQL))
++ if (!wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))
+ return true;
+
+ if (!txq->sta)
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