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>

1 files changed, 25 insertions, 17 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index d6754908ff79..a1029449df44 100644
--- a/net/mac80211/tx.c
+++ b/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);
-                if (skb) {
-                        purged++;
-                        dev_kfree_skb(skb);
+                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,