wifi: mac80211: rework ack_frame_id handling a bit

Take one more free bit to indicate it's IDR vs. internal
usage, to be able to carve out some bits here for other
internal usage, other than IDR handling with a full ACK
SKB, that is.
Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -1115,7 +1115,9 @@ ieee80211_rate_get_vht_nss(const struct ieee80211_tx_rate *rate)
  *	not valid if the interface is an MLD since we won't know which
  *	link the frame will be transmitted on
  * @hw_queue: HW queue to put the frame on, skb_get_queue_mapping() gives the AC
- * @ack_frame_id: internal frame ID for TX status, used internally
+ * @status_data: internal data for TX status handling, assigned privately,
+ *	see also &enum ieee80211_status_data for the internal documentation
+ * @status_data_idr: indicates status data is IDR allocated ID for ack frame
  * @tx_time_est: TX time estimate in units of 4us, used internally
  * @control: union part for control data
  * @control.rates: TX rates array to try
@@ -1155,10 +1157,11 @@ struct ieee80211_tx_info {
 	/* common information */
 	u32 flags;
 	u32 band:3,
-	    ack_frame_id:13,
+	    status_data_idr:1,
+	    status_data:13,
 	    hw_queue:4,
 	    tx_time_est:10;
-	/* 2 free bits */
+	/* 1 free bit */
 
 	union {
 		struct {

net/mac80211/cfg.c

@@ -4034,7 +4034,8 @@ int ieee80211_attach_ack_skb(struct ieee80211_local *local, struct sk_buff *skb,
 		return -ENOMEM;
 	}
 
-	IEEE80211_SKB_CB(skb)->ack_frame_id = id;
+	IEEE80211_SKB_CB(skb)->status_data_idr = 1;
+	IEEE80211_SKB_CB(skb)->status_data = id;
 
 	*cookie = ieee80211_mgmt_tx_cookie(local);
 	IEEE80211_SKB_CB(ack_skb)->ack.cookie = *cookie;

net/mac80211/ieee80211_i.h

@@ -85,6 +85,11 @@ extern const u8 ieee80211_ac_to_qos_mask[IEEE80211_NUM_ACS];
 
 #define IEEE80211_MAX_NAN_INSTANCE_ID 255
 
+enum ieee80211_status_data {
+	IEEE80211_STATUS_TYPE_MASK	= 0x00f,
+	IEEE80211_STATUS_TYPE_INVALID	= 0,
+	IEEE80211_STATUS_SUBDATA_MASK	= 0xff0,
+};
 
 /*
  * Keep a station's queues on the active list for deficit accounting purposes

net/mac80211/status.c

@@ -633,7 +633,7 @@ static void ieee80211_report_ack_skb(struct ieee80211_local *local,
 	unsigned long flags;
 
 	spin_lock_irqsave(&local->ack_status_lock, flags);
-	skb = idr_remove(&local->ack_status_frames, info->ack_frame_id);
+	skb = idr_remove(&local->ack_status_frames, info->status_data);
 	spin_unlock_irqrestore(&local->ack_status_lock, flags);
 
 	if (!skb)
@@ -759,7 +759,7 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
 		}
 
 		rcu_read_unlock();
-	} else if (info->ack_frame_id) {
+	} else if (info->status_data_idr) {
 		ieee80211_report_ack_skb(local, skb, acked, dropped,
 					 ack_hwtstamp);
 	}

net/mac80211/tx.c

@@ -2942,7 +2942,10 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
 	memset(info, 0, sizeof(*info));
 
 	info->flags = info_flags;
-	info->ack_frame_id = info_id;
+	if (info_id) {
+		info->status_data = info_id;
+		info->status_data_idr = 1;
+	}
 	info->band = band;
 
 	if (likely(!cookie)) {
@@ -4639,9 +4642,12 @@ static void ieee80211_8023_xmit(struct ieee80211_sub_if_data *sdata,
 	}
 
 	if (unlikely(skb->sk &&
-		     skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS))
-		info->ack_frame_id = ieee80211_store_ack_skb(local, skb,
-							     &info->flags, NULL);
+		     skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS)) {
+		info->status_data = ieee80211_store_ack_skb(local, skb,
+							    &info->flags, NULL);
+		if (info->status_data)
+			info->status_data_idr = 1;
+	}
 
 	dev_sw_netstats_tx_add(dev, skbs, len);
 	sta->deflink.tx_stats.packets[queue] += skbs;