mac80211: redesign scan RX

Scan receive is rather inefficient when there are
multiple virtual interfaces. We iterate all of the
virtual interfaces and then notify cfg80211 about
each beacon many times.

Redesign scan RX to happen before everything else.
Then we can also get rid of IEEE80211_RX_IN_SCAN
since we don't have to accept frames into the RX
handlers for scanning or scheduled scanning any
more. Overall, this simplifies the code.

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

1 files changed, 23 insertions, 34 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index a619c1e..1a893f3 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -165,52 +165,47 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 	return bss;
 }
 
-ieee80211_rx_result
-ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
+void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 {
 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
-	struct ieee80211_mgmt *mgmt;
+	struct ieee80211_sub_if_data *sdata1, *sdata2;
+	struct ieee80211_mgmt *mgmt = (void *)skb->data;
 	struct ieee80211_bss *bss;
 	u8 *elements;
 	struct ieee80211_channel *channel;
 	size_t baselen;
 	int freq;
-	__le16 fc;
-	bool presp, beacon = false;
+	bool beacon;
 	struct ieee802_11_elems elems;
 
-	if (skb->len < 2)
-		return RX_DROP_UNUSABLE;
-
-	mgmt = (struct ieee80211_mgmt *) skb->data;
-	fc = mgmt->frame_control;
+	if (skb->len < 24 ||
+	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
+	     !ieee80211_is_beacon(mgmt->frame_control)))
+		return;
 
-	if (ieee80211_is_ctl(fc))
-		return RX_CONTINUE;
+	sdata1 = rcu_dereference(local->scan_sdata);
+	sdata2 = rcu_dereference(local->sched_scan_sdata);
 
-	if (skb->len < 24)
-		return RX_CONTINUE;
+	if (likely(!sdata1 && !sdata2))
+		return;
 
-	presp = ieee80211_is_probe_resp(fc);
-	if (presp) {
+	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 		/* ignore ProbeResp to foreign address */
-		if (!ether_addr_equal(mgmt->da, sdata->vif.addr))
-			return RX_DROP_MONITOR;
+		if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
+		    (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
+			return;
 
-		presp = true;
 		elements = mgmt->u.probe_resp.variable;
 		baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
+		beacon = false;
 	} else {
-		beacon = ieee80211_is_beacon(fc);
 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 		elements = mgmt->u.beacon.variable;
+		beacon = true;
 	}
 
-	if (!presp && !beacon)
-		return RX_CONTINUE;
-
 	if (baselen > skb->len)
-		return RX_DROP_MONITOR;
+		return;
 
 	ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 
@@ -220,22 +215,16 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 	else
 		freq = rx_status->freq;
 
-	channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
+	channel = ieee80211_get_channel(local->hw.wiphy, freq);
 
 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
-		return RX_DROP_MONITOR;
+		return;
 
-	bss = ieee80211_bss_info_update(sdata->local, rx_status,
+	bss = ieee80211_bss_info_update(local, rx_status,
 					mgmt, skb->len, &elems,
 					channel, beacon);
 	if (bss)
-		ieee80211_rx_bss_put(sdata->local, bss);
-
-	if (channel == sdata->local->oper_channel)
-		return RX_CONTINUE;
-
-	dev_kfree_skb(skb);
-	return RX_QUEUED;
+		ieee80211_rx_bss_put(local, bss);
 }
 
 /* return false if no more work */