mac80211: add fast-rx path

The regular RX path has a lot of code, but with a few
assumptions on the hardware it's possible to reduce the
amount of code significantly. Currently the assumptions
on the driver are the following:
 * hardware/driver reordering buffer (if supporting aggregation)
 * hardware/driver decryption & PN checking (if using encryption)
 * hardware/driver did de-duplication
 * hardware/driver did A-MSDU deaggregation
 * AP_LINK_PS is used (in AP mode)
 * no client powersave handling in mac80211 (in client mode)

of which some are actually checked per packet:
 * de-duplication
 * PN checking
 * decryption
and additionally packets must
 * not be A-MSDU (have been deaggregated by driver/device)
 * be data packets
 * not be fragmented
 * be unicast
 * have RFC 1042 header

Additionally dynamically we assume:
 * no encryption or CCMP/GCMP, TKIP/WEP/other not allowed
 * station must be authorized
 * 4-addr format not enabled

Some data needed for the RX path is cached in a new per-station
"fast_rx" structure, so that we only need to look at this and
the packet, no other memory when processing packets on the fast
RX path.

After doing the above per-packet checks, the data path collapses
down to a pretty simple conversion function taking advantage of
the data cached in the small fast_rx struct.

This should speed up the RX processing, and will make it easier
to reason about parallelizing RX (for which statistics will need
to be per-CPU still.)

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

1 files changed, 9 insertions, 0 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 2112df4ffb7b..d3c75ac8a029 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2217,6 +2217,7 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
 	const u8 *ssid;
 	u8 *dst = ifmgd->associated->bssid;
 	u8 unicast_limit = max(1, max_probe_tries - 3);
+	struct sta_info *sta;
 
 	/*
 	 * Try sending broadcast probe requests for the last three
@@ -2235,6 +2236,14 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
 	 */
 	ifmgd->probe_send_count++;
 
+	if (dst) {
+		mutex_lock(&sdata->local->sta_mtx);
+		sta = sta_info_get(sdata, dst);
+		if (!WARN_ON(!sta))
+			ieee80211_check_fast_rx(sta);
+		mutex_unlock(&sdata->local->sta_mtx);
+	}
+
 	if (ieee80211_hw_check(&sdata->local->hw, REPORTS_TX_ACK_STATUS)) {
 		ifmgd->nullfunc_failed = false;
 		ieee80211_send_nullfunc(sdata->local, sdata, false);