mac80211: split PS buffers into ACs

For uAPSD support we'll need to have per-AC PS
buffers. As this is a major undertaking, split
the buffers before really adding support for
uAPSD. This already makes some reference to the
uapsd_queues variable, but for now that will
never be non-zero.

Since book-keeping is complicated, also change
the logic for keeping a maximum of frames only
and allow 64 frames per AC (up from 128 for a
station).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/mac80211.h

@@ -109,6 +109,7 @@ enum ieee80211_ac_numbers {
 	IEEE80211_AC_BE		= 2,
 	IEEE80211_AC_BK		= 3,
 };
+#define IEEE80211_NUM_ACS	4
 
 /**
  * struct ieee80211_tx_queue_params - transmit queue configuration

net/mac80211/debugfs_sta.c

@@ -78,8 +78,14 @@ static ssize_t sta_num_ps_buf_frames_read(struct file *file,
 					  size_t count, loff_t *ppos)
 {
 	struct sta_info *sta = file->private_data;
-	return mac80211_format_buffer(userbuf, count, ppos, "%u\n",
-				      skb_queue_len(&sta->ps_tx_buf));
+	char buf[17*IEEE80211_NUM_ACS], *p = buf;
+	int ac;
+
+	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
+		p += scnprintf(p, sizeof(buf)+buf-p, "AC%d: %d\n", ac,
+			       skb_queue_len(&sta->ps_tx_buf[ac]) +
+			       skb_queue_len(&sta->tx_filtered[ac]));
+	return simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
 }
 STA_OPS(num_ps_buf_frames);
 

net/mac80211/sta_info.h

@@ -43,8 +43,6 @@
  *	be in the queues
  * @WLAN_STA_PSPOLL: Station sent PS-poll while driver was keeping
  *	station in power-save mode, reply when the driver unblocks.
- * @WLAN_STA_PS_DRIVER_BUF: Station has frames pending in driver internal
- *	buffers. Automatically cleared on station wake-up.
  * @WLAN_STA_TDLS_PEER: Station is a TDLS peer.
  * @WLAN_STA_TDLS_PEER_AUTH: This TDLS peer is authorized to send direct
  *	packets. This means the link is enabled.
@@ -63,7 +61,6 @@ enum ieee80211_sta_info_flags {
 	WLAN_STA_BLOCK_BA	= 1<<11,
 	WLAN_STA_PS_DRIVER	= 1<<12,
 	WLAN_STA_PSPOLL		= 1<<13,
-	WLAN_STA_PS_DRIVER_BUF	= 1<<14,
 	WLAN_STA_TDLS_PEER	= 1<<15,
 	WLAN_STA_TDLS_PEER_AUTH	= 1<<16,
 };
@@ -212,11 +209,13 @@ struct sta_ampdu_mlme {
  * @drv_unblock_wk: used for driver PS unblocking
  * @listen_interval: listen interval of this station, when we're acting as AP
  * @flags: STA flags, see &enum ieee80211_sta_info_flags
- * @ps_tx_buf: buffer of frames to transmit to this station
- *	when it leaves power saving state
- * @tx_filtered: buffer of frames we already tried to transmit
- *	but were filtered by hardware due to STA having entered
- *	power saving state
+ * @ps_tx_buf: buffers (per AC) of frames to transmit to this station
+ *	when it leaves power saving state or polls
+ * @tx_filtered: buffers (per AC) of frames we already tried to
+ *	transmit but were filtered by hardware due to STA having
+ *	entered power saving state, these are also delivered to
+ *	the station when it leaves powersave or polls for frames
+ * @driver_buffered_tids: bitmap of TIDs the driver has data buffered on
  * @rx_packets: Number of MSDUs received from this STA
  * @rx_bytes: Number of bytes received from this STA
  * @wep_weak_iv_count: number of weak WEP IVs received from this station
@@ -286,8 +285,9 @@ struct sta_info {
 	 * STA powersave frame queues, no more than the internal
 	 * locking required.
 	 */
-	struct sk_buff_head ps_tx_buf;
-	struct sk_buff_head tx_filtered;
+	struct sk_buff_head ps_tx_buf[IEEE80211_NUM_ACS];
+	struct sk_buff_head tx_filtered[IEEE80211_NUM_ACS];
+	unsigned long driver_buffered_tids;
 
 	/* Updated from RX path only, no locking requirements */
 	unsigned long rx_packets, rx_bytes;
@@ -434,8 +434,8 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
 #define STA_HASH(sta) (sta[5])
 
 
-/* Maximum number of frames to buffer per power saving station */
-#define STA_MAX_TX_BUFFER 128
+/* Maximum number of frames to buffer per power saving station per AC */
+#define STA_MAX_TX_BUFFER	64
 
 /* Minimum buffered frame expiry time. If STA uses listen interval that is
  * smaller than this value, the minimum value here is used instead. */

net/mac80211/status.c

@@ -14,6 +14,7 @@
 #include "rate.h"
 #include "mesh.h"
 #include "led.h"
+#include "wme.h"
 
 
 void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
@@ -43,6 +44,8 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 					    struct sk_buff *skb)
 {
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_hdr *hdr = (void *)skb->data;
+	int ac;
 
 	/*
 	 * This skb 'survived' a round-trip through the driver, and
@@ -62,6 +65,14 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 
 	sta->tx_filtered_count++;
 
+	if (ieee80211_is_data_qos(hdr->frame_control)) {
+		int tid = *ieee80211_get_qos_ctl(hdr) &
+					IEEE80211_QOS_CTL_TID_MASK;
+		ac = ieee802_1d_to_ac[tid & 7];
+	} else {
+		ac = IEEE80211_AC_BE;
+	}
+
 	/*
 	 * Clear the TX filter mask for this STA when sending the next
 	 * packet. If the STA went to power save mode, this will happen
@@ -104,8 +115,8 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 	 *	unknown.
 	 */
 	if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
-	    skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
-		skb_queue_tail(&sta->tx_filtered, skb);
+	    skb_queue_len(&sta->tx_filtered[ac]) < STA_MAX_TX_BUFFER) {
+		skb_queue_tail(&sta->tx_filtered[ac], skb);
 		sta_info_recalc_tim(sta);
 
 		if (!timer_pending(&local->sta_cleanup))
@@ -127,7 +138,7 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 	if (net_ratelimit())
 		wiphy_debug(local->hw.wiphy,
 			    "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
-			    skb_queue_len(&sta->tx_filtered),
+			    skb_queue_len(&sta->tx_filtered[ac]),
 			    !!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
 #endif
 	dev_kfree_skb(skb);

net/mac80211/tx.c

@@ -343,13 +343,22 @@ static void purge_old_ps_buffers(struct ieee80211_local *local)
 		total += skb_queue_len(&ap->ps_bc_buf);
 	}
 
+	/*
+	 * Drop one frame from each station from the lowest-priority
+	 * AC that has frames at all.
+	 */
 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
-		skb = skb_dequeue(&sta->ps_tx_buf);
+		int ac;
+
+		for (ac = IEEE80211_AC_BK; ac >= IEEE80211_AC_VO; ac--) {
+			skb = skb_dequeue(&sta->ps_tx_buf[ac]);
+			total += skb_queue_len(&sta->ps_tx_buf[ac]);
 			if (skb) {
 				purged++;
 				dev_kfree_skb(skb);
+				break;
+			}
 		}
-		total += skb_queue_len(&sta->ps_tx_buf);
 	}
 
 	rcu_read_unlock();
@@ -448,22 +457,21 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 
 	if (unlikely((staflags & (WLAN_STA_PS_STA | WLAN_STA_PS_DRIVER)) &&
 		     !(info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE))) {
+		int ac = skb_get_queue_mapping(tx->skb);
+
 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
-		printk(KERN_DEBUG "STA %pM aid %d: PS buffer (entries "
-		       "before %d)\n",
-		       sta->sta.addr, sta->sta.aid,
-		       skb_queue_len(&sta->ps_tx_buf));
+		printk(KERN_DEBUG "STA %pM aid %d: PS buffer for AC %d\n",
+		       sta->sta.addr, sta->sta.aid, ac);
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
 		if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
 			purge_old_ps_buffers(tx->local);
-		if (skb_queue_len(&sta->ps_tx_buf) >= STA_MAX_TX_BUFFER) {
-			struct sk_buff *old = skb_dequeue(&sta->ps_tx_buf);
+		if (skb_queue_len(&sta->ps_tx_buf[ac]) >= STA_MAX_TX_BUFFER) {
+			struct sk_buff *old = skb_dequeue(&sta->ps_tx_buf[ac]);
 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
-			if (net_ratelimit()) {
-				printk(KERN_DEBUG "%s: STA %pM TX "
-				       "buffer full - dropping oldest frame\n",
-				       tx->sdata->name, sta->sta.addr);
-			}
+			if (net_ratelimit())
+				printk(KERN_DEBUG "%s: STA %pM TX buffer for "
+				       "AC %d full - dropping oldest frame\n",
+				       tx->sdata->name, sta->sta.addr, ac);
 #endif
 			dev_kfree_skb(old);
 		} else
@@ -472,7 +480,7 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 		info->control.jiffies = jiffies;
 		info->control.vif = &tx->sdata->vif;
 		info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
-		skb_queue_tail(&sta->ps_tx_buf, tx->skb);
+		skb_queue_tail(&sta->ps_tx_buf[ac], tx->skb);
 
 		if (!timer_pending(&local->sta_cleanup))
 			mod_timer(&local->sta_cleanup,