Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: [PATCH RFC/RFT 2/4] mac80211: Add API function to set the last TX
 bitrate for a station
From:   =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org,
        make-wifi-fast@lists.bufferbloat.net,
        John Crispin <john@phrozen.org>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Felix Fietkau <nbd@nbd.name>
Date:   Thu, 19 Sep 2019 14:22:46 +0200
Message-ID: <156889576646.191202.14461472477971784776.stgit@alrua-x1>
In-Reply-To: <156889576422.191202.5906619710809654631.stgit@alrua-x1>
References: <156889576422.191202.5906619710809654631.stgit@alrua-x1>
User-Agent: StGit/0.19-dirty
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

From: Toke H=C3=B8iland-J=C3=B8rgensen <toke@redhat.com>

To implement airtime queue limits, we need an estimate of the transmission
rate a station is currently transmitting at. The ath10k driver already
keeps this internally, so add an API function to pass this up to mac80211.

We also keep a pre-calculated 64-bit reciprocal that will be used in the
actual calculations, to avoid a division operation in the fast path.

Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen <toke@redhat.com>
---
 include/net/mac80211.h     |   10 ++++++++++
 net/mac80211/ieee80211_i.h |    4 ++++
 net/mac80211/sta_info.c    |    9 +++++++++
 net/mac80211/sta_info.h    |    2 ++
 4 files changed, 25 insertions(+)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index b12d378621b0..1b7f4a370122 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -4529,6 +4529,16 @@ void ieee80211_get_tx_rates(struct ieee80211_vif *vi=
f,
 void ieee80211_sta_set_expected_throughput(struct ieee80211_sta *pubsta,
 =09=09=09=09=09   u32 thr);
=20
+/**
+ * ieee80211_sta_set_last_tx_bitrate - set last tx rate for station
+ *
+ * This sets the last TX bitrate for a given station.
+ *
+ * @sta: Pointer to the station
+ * @bitrate: Bitrate in kbps
+ */
+void ieee80211_sta_set_last_tx_bitrate(struct ieee80211_sta *sta, u32 bitr=
ate);
+
 /**
  * ieee80211_tx_rate_update - transmit rate update callback
  *
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 05406e9c05b3..9de5390411ba 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -59,6 +59,10 @@ struct ieee80211_local;
 /* power level hasn't been configured (or set to automatic) */
 #define IEEE80211_UNSET_POWER_LEVEL=09INT_MIN
=20
+/* constants for calculating reciprocals to avoid division in fast path */
+#define IEEE80211_RECIPROCAL_DIVISOR 0x100000000ULL
+#define IEEE80211_RECIPROCAL_SHIFT 32
+
 /*
  * Some APs experience problems when working with U-APSD. Decreasing the
  * probability of that happening by using legacy mode for all ACs but VO i=
sn't
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index df553070206c..aae878ffe94c 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -2481,3 +2481,12 @@ void ieee80211_sta_set_expected_throughput(struct ie=
ee80211_sta *pubsta,
=20
 =09sta_update_codel_params(sta, thr);
 }
+
+void ieee80211_sta_set_last_tx_bitrate(struct ieee80211_sta *pubsta,
+=09=09=09=09       u32 rate)
+{
+=09struct sta_info *sta =3D container_of(pubsta, struct sta_info, sta);
+
+=09sta->last_tx_bitrate =3D rate;
+=09sta->last_tx_bitrate_reciprocal =3D ((u64)IEEE80211_RECIPROCAL_DIVISOR =
/ rate);
+}
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 369c2dddce52..dd1a0b87f234 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -617,6 +617,8 @@ struct sta_info {
 =09const struct ieee80211_cipher_scheme *cipher_scheme;
=20
 =09struct codel_params cparams;
+=09u32 last_tx_bitrate;
+=09u64 last_tx_bitrate_reciprocal;
=20
 =09u8 reserved_tid;
=20