mac80211: synchronously reserve TID per station

In TDLS (e.g., TDLS off-channel) there is a requirement for
some drivers to supply an unused TID between the AP and the
device to the FW, to allow sending PTI requests and to allow
the FW to aggregate on a specific TID for better throughput.

To ensure that the allocated TID is indeed unused, this patch
introduces an API for blocking the driver from TXing on that
TID.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 56b7e2114728cfad95f9a10fd22627b91d92aa74..59166a115affceec18a4e25accecf1090f81dff7 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -5070,6 +5070,43 @@ void ieee80211_tdls_oper_request(struct ieee80211_vif *vif, const u8 *peer,
                                 enum nl80211_tdls_operation oper,
                                 u16 reason_code, gfp_t gfp);
 
+/**
+ * ieee80211_reserve_tid - request to reserve a specific TID
+ *
+ * There is sometimes a need (such as in TDLS) for blocking the driver from
+ * using a specific TID so that the FW can use it for certain operations such
+ * as sending PTI requests. To make sure that the driver doesn't use that TID,
+ * this function must be called as it flushes out packets on this TID and marks
+ * it as blocked, so that any transmit for the station on this TID will be
+ * redirected to the alternative TID in the same AC.
+ *
+ * Note that this function blocks and may call back into the driver, so it
+ * should be called without driver locks held. Also note this function should
+ * only be called from the driver's @sta_state callback.
+ *
+ * @sta: the station to reserve the TID for
+ * @tid: the TID to reserve
+ *
+ * Returns: 0 on success, else on failure
+ */
+int ieee80211_reserve_tid(struct ieee80211_sta *sta, u8 tid);
+
+/**
+ * ieee80211_unreserve_tid - request to unreserve a specific TID
+ *
+ * Once there is no longer any need for reserving a certain TID, this function
+ * should be called, and no longer will packets have their TID modified for
+ * preventing use of this TID in the driver.
+ *
+ * Note that this function blocks and acquires a lock, so it should be called
+ * without driver locks held. Also note this function should only be called
+ * from the driver's @sta_state callback.
+ *
+ * @sta: the station
+ * @tid: the TID to unreserve
+ */
+void ieee80211_unreserve_tid(struct ieee80211_sta *sta, u8 tid);
+
 /**
  * ieee80211_ie_split - split an IE buffer according to ordering
  *

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 9242c60048cf960ef30e988ee87f4d870e6f95ab..a360c15cc978b0a6c396e0a18a07cdfd5e3154e5 100644 (file)
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -509,6 +509,10 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
        struct tid_ampdu_tx *tid_tx;
        int ret = 0;
 
+       if (WARN(sta->reserved_tid == tid,
+                "Requested to start BA session on reserved tid=%d", tid))
+               return -EINVAL;
+
        trace_api_start_tx_ba_session(pubsta, tid);
 
        if (WARN_ON_ONCE(!local->ops->ampdu_action))
@@ -765,6 +769,9 @@ int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
                goto unlock;
        }
 
+       WARN(sta->reserved_tid == tid,
+            "Requested to stop BA session on reserved tid=%d", tid);
+
        if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
                /* already in progress stopping it */
                ret = 0;

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a30d40839d49d2833781a1bf95c95a61223e316a..34168c21bf06dcaeff012ae0397e02a7971fa7e5 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1011,6 +1011,7 @@ enum queue_stop_reason {
        IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
        IEEE80211_QUEUE_STOP_REASON_FLUSH,
        IEEE80211_QUEUE_STOP_REASON_TDLS_TEARDOWN,
+       IEEE80211_QUEUE_STOP_REASON_RESERVE_TID,
 
        IEEE80211_QUEUE_STOP_REASONS,
 };

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 86ca6276569942b26199f6954bab0681ed9050af..a42f5b2b024d640260ce646acccad73c819a36a4 100644 (file)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -351,6 +351,9 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 
        sta->sta_state = IEEE80211_STA_NONE;
 
+       /* Mark TID as unreserved */
+       sta->reserved_tid = IEEE80211_TID_UNRESERVED;
+
        ktime_get_ts(&uptime);
        sta->last_connected = uptime.tv_sec;
        ewma_init(&sta->avg_signal, 1024, 8);

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 00f56eb72c601c5b70306083649c642c65f68fb4..4f052bb2a5adaf0a1d49ad49c6a27b59963fecb6 100644 (file)
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -254,6 +254,9 @@ struct ieee80211_tx_latency_stat {
        u32 bin_count;
 };
 
+/* Value to indicate no TID reservation */
+#define IEEE80211_TID_UNRESERVED       0xff
+
 /**
  * struct sta_info - STA information
  *
@@ -342,6 +345,7 @@ struct ieee80211_tx_latency_stat {
  *     AP only.
  * @cipher_scheme: optional cipher scheme for this station
  * @last_tdls_pkt_time: holds the time in jiffies of last TDLS pkt ACKed
+ * @reserved_tid: reserved TID (if any, otherwise IEEE80211_TID_UNRESERVED)
  */
 struct sta_info {
        /* General information, mostly static */
@@ -459,6 +463,8 @@ struct sta_info {
        /* TDLS timeout data */
        unsigned long last_tdls_pkt_time;
 
+       u8 reserved_tid;
+
        /* keep last! */
        struct ieee80211_sta sta;
 };

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 2dd89670e1cdc21f238b8a8ed57ae7463eafe7b1..0cb41d1a1f208b23e2843862e6ddbe111bdf4165 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3107,6 +3107,97 @@ ieee80211_get_buffered_bc(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL(ieee80211_get_buffered_bc);
 
+int ieee80211_reserve_tid(struct ieee80211_sta *pubsta, u8 tid)
+{
+       struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
+       struct ieee80211_sub_if_data *sdata = sta->sdata;
+       struct ieee80211_local *local = sdata->local;
+       int ret;
+       u32 queues;
+
+       lockdep_assert_held(&local->sta_mtx);
+
+       /* only some cases are supported right now */
+       switch (sdata->vif.type) {
+       case NL80211_IFTYPE_STATION:
+       case NL80211_IFTYPE_AP:
+       case NL80211_IFTYPE_AP_VLAN:
+               break;
+       default:
+               WARN_ON(1);
+               return -EINVAL;
+       }
+
+       if (WARN_ON(tid >= IEEE80211_NUM_UPS))
+               return -EINVAL;
+
+       if (sta->reserved_tid == tid) {
+               ret = 0;
+               goto out;
+       }
+
+       if (sta->reserved_tid != IEEE80211_TID_UNRESERVED) {
+               sdata_err(sdata, "TID reservation already active\n");
+               ret = -EALREADY;
+               goto out;
+       }
+
+       ieee80211_stop_vif_queues(sdata->local, sdata,
+                                 IEEE80211_QUEUE_STOP_REASON_RESERVE_TID);
+
+       synchronize_net();
+
+       /* Tear down BA sessions so we stop aggregating on this TID */
+       if (local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION) {
+               set_sta_flag(sta, WLAN_STA_BLOCK_BA);
+               __ieee80211_stop_tx_ba_session(sta, tid,
+                                              AGG_STOP_LOCAL_REQUEST);
+       }
+
+       queues = BIT(sdata->vif.hw_queue[ieee802_1d_to_ac[tid]]);
+       __ieee80211_flush_queues(local, sdata, queues);
+
+       sta->reserved_tid = tid;
+
+       ieee80211_wake_vif_queues(local, sdata,
+                                 IEEE80211_QUEUE_STOP_REASON_RESERVE_TID);
+
+       if (local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION)
+               clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
+
+       ret = 0;
+ out:
+       return ret;
+}
+EXPORT_SYMBOL(ieee80211_reserve_tid);
+
+void ieee80211_unreserve_tid(struct ieee80211_sta *pubsta, u8 tid)
+{
+       struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
+       struct ieee80211_sub_if_data *sdata = sta->sdata;
+
+       lockdep_assert_held(&sdata->local->sta_mtx);
+
+       /* only some cases are supported right now */
+       switch (sdata->vif.type) {
+       case NL80211_IFTYPE_STATION:
+       case NL80211_IFTYPE_AP:
+       case NL80211_IFTYPE_AP_VLAN:
+               break;
+       default:
+               WARN_ON(1);
+               return;
+       }
+
+       if (tid != sta->reserved_tid) {
+               sdata_err(sdata, "TID to unreserve (%d) isn't reserved\n", tid);
+               return;
+       }
+
+       sta->reserved_tid = IEEE80211_TID_UNRESERVED;
+}
+EXPORT_SYMBOL(ieee80211_unreserve_tid);
+
 void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
                                 struct sk_buff *skb, int tid,
                                 enum ieee80211_band band)

diff --git a/net/mac80211/wme.c b/net/mac80211/wme.c
index fdf52db95b33303d791c638410ebd8591a239ae3..9eb0aee9105b398b442380315ec758a430a103b1 100644 (file)
--- a/net/mac80211/wme.c
+++ b/net/mac80211/wme.c
@@ -53,6 +53,36 @@ static int wme_downgrade_ac(struct sk_buff *skb)
        }
 }
 
+/**
+ * ieee80211_fix_reserved_tid - return the TID to use if this one is reserved
+ * @tid: the assumed-reserved TID
+ *
+ * Returns: the alternative TID to use, or 0 on error
+ */
+static inline u8 ieee80211_fix_reserved_tid(u8 tid)
+{
+       switch (tid) {
+       case 0:
+               return 3;
+       case 1:
+               return 2;
+       case 2:
+               return 1;
+       case 3:
+               return 0;
+       case 4:
+               return 5;
+       case 5:
+               return 4;
+       case 6:
+               return 7;
+       case 7:
+               return 6;
+       }
+
+       return 0;
+}
+
 static u16 ieee80211_downgrade_queue(struct ieee80211_sub_if_data *sdata,
                                     struct sta_info *sta, struct sk_buff *skb)
 {
@@ -77,6 +107,10 @@ static u16 ieee80211_downgrade_queue(struct ieee80211_sub_if_data *sdata,
                }
        }
 
+       /* Check to see if this is a reserved TID */
+       if (sta && sta->reserved_tid == skb->priority)
+               skb->priority = ieee80211_fix_reserved_tid(skb->priority);
+
        /* look up which queue to use for frames with this 1d tag */
        return ieee802_1d_to_ac[skb->priority];
 }
@@ -143,6 +177,11 @@ u16 ieee80211_select_queue(struct ieee80211_sub_if_data *sdata,
                break;
 #endif
        case NL80211_IFTYPE_STATION:
+               /* might be a TDLS station */
+               sta = sta_info_get(sdata, skb->data);
+               if (sta)
+                       qos = sta->sta.wme;
+
                ra = sdata->u.mgd.bssid;
                break;
        case NL80211_IFTYPE_ADHOC: