mac80211: consolidate TIM handling code

This consolidates all TIM handling code to avoid re-introducing
errors with the bitmap/set_tim order and to reduce code. While
reading the code I noticed a possible problem so I also added
a comment about that.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 84 insertions, 83 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 1b4a4497030d..b07b3cbfd039 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -207,7 +207,7 @@ struct ieee80211_if_ap {
 
         /* yes, this looks ugly, but guarantees that we can later use
          * bitmap_empty :)
-         * NB: don't ever use set_bit, use bss_tim_set/bss_tim_clear! */
+         * NB: don't touch this bitmap, use sta_info_{set,clear}_tim_bit */
         u8 tim[sizeof(unsigned long) * BITS_TO_LONGS(IEEE80211_MAX_AID + 1)];
         atomic_t num_sta_ps; /* number of stations in PS mode */
         struct sk_buff_head ps_bc_buf;
@@ -640,40 +640,6 @@ struct sta_attribute {
         ssize_t (*store)(struct sta_info *, const char *buf, size_t count);
 };
 
-static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
-{
-        /*
-         * This format has been mandated by the IEEE specifications,
-         * so this line may not be changed to use the __set_bit() format.
-         */
-        bss->tim[aid / 8] |= (1 << (aid % 8));
-}
-
-static inline void bss_tim_set(struct ieee80211_local *local,
-                               struct ieee80211_if_ap *bss, u16 aid)
-{
-        read_lock_bh(&local->sta_lock);
-        __bss_tim_set(bss, aid);
-        read_unlock_bh(&local->sta_lock);
-}
-
-static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
-{
-        /*
-         * This format has been mandated by the IEEE specifications,
-         * so this line may not be changed to use the __clear_bit() format.
-         */
-        bss->tim[aid / 8] &= ~(1 << (aid % 8));
-}
-
-static inline void bss_tim_clear(struct ieee80211_local *local,
-                                 struct ieee80211_if_ap *bss, u16 aid)
-{
-        read_lock_bh(&local->sta_lock);
-        __bss_tim_clear(bss, aid);
-        read_unlock_bh(&local->sta_lock);
-}
-
 static inline int ieee80211_bssid_match(const u8 *raddr, const u8 *addr)
 {
         return compare_ether_addr(raddr, addr) == 0 ||
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 0e8a371496b3..48574f6c0e74 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -596,19 +596,20 @@ static int ap_sta_ps_end(struct net_device *dev, struct sta_info *sta)
         DECLARE_MAC_BUF(mac);
 
         sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+
         if (sdata->bss)
                 atomic_dec(&sdata->bss->num_sta_ps);
+
         sta->flags &= ~(WLAN_STA_PS | WLAN_STA_PSPOLL);
-        if (!skb_queue_empty(&sta->ps_tx_buf)) {
-                if (sdata->bss)
-                        bss_tim_clear(local, sdata->bss, sta->aid);
-                if (local->ops->set_tim)
-                        local->ops->set_tim(local_to_hw(local), sta->aid, 0);
-        }
+
+        if (!skb_queue_empty(&sta->ps_tx_buf))
+                sta_info_clear_tim_bit(sta);
+
 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
         printk(KERN_DEBUG "%s: STA %s aid %d exits power save mode\n",
                dev->name, print_mac(mac, sta->addr), sta->aid);
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
+
         /* Send all buffered frames to the station */
         while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL) {
                 pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
@@ -945,20 +946,20 @@ ieee80211_rx_h_ps_poll(struct ieee80211_txrx_data *rx)
 
                 dev_queue_xmit(skb);
 
-                if (no_pending_pkts) {
-                        if (rx->sdata->bss)
-                                bss_tim_clear(rx->local, rx->sdata->bss, rx->sta->aid);
-                        if (rx->local->ops->set_tim)
-                                rx->local->ops->set_tim(local_to_hw(rx->local),
-                                                       rx->sta->aid, 0);
-                }
+                if (no_pending_pkts)
+                        sta_info_clear_tim_bit(rx->sta);
 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
         } else if (!rx->u.rx.sent_ps_buffered) {
+                /*
+                 * FIXME: This can be the result of a race condition between
+                 *        us expiring a frame and the station polling for it.
+                 *        Should we send it a null-func frame indicating we
+                 *        have nothing buffered for it?
+                 */
                 printk(KERN_DEBUG "%s: STA %s sent PS Poll even "
                        "though there is no buffered frames for it\n",
                        rx->dev->name, print_mac(mac, rx->sta->addr));
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
-
         }
 
         /* Free PS Poll skb here instead of returning RX_DROP that would
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index a843bb7dd2d3..b31a627ff97f 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -191,6 +191,64 @@ struct sta_info * sta_info_add(struct ieee80211_local *local,
         return sta;
 }
 
+static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
+{
+        /*
+         * This format has been mandated by the IEEE specifications,
+         * so this line may not be changed to use the __set_bit() format.
+         */
+        bss->tim[aid / 8] |= (1 << (aid % 8));
+}
+
+static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
+{
+        /*
+         * This format has been mandated by the IEEE specifications,
+         * so this line may not be changed to use the __clear_bit() format.
+         */
+        bss->tim[aid / 8] &= ~(1 << (aid % 8));
+}
+
+static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
+                                   struct sta_info *sta)
+{
+        if (bss)
+                __bss_tim_set(bss, sta->aid);
+        if (sta->local->ops->set_tim)
+                sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
+}
+
+void sta_info_set_tim_bit(struct sta_info *sta)
+{
+        struct ieee80211_sub_if_data *sdata;
+
+        sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+
+        read_lock_bh(&sta->local->sta_lock);
+        __sta_info_set_tim_bit(sdata->bss, sta);
+        read_unlock_bh(&sta->local->sta_lock);
+}
+
+static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
+                                     struct sta_info *sta)
+{
+        if (bss)
+                __bss_tim_clear(bss, sta->aid);
+        if (sta->local->ops->set_tim)
+                sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
+}
+
+void sta_info_clear_tim_bit(struct sta_info *sta)
+{
+        struct ieee80211_sub_if_data *sdata;
+
+        sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+
+        read_lock_bh(&sta->local->sta_lock);
+        __sta_info_clear_tim_bit(sdata->bss, sta);
+        read_unlock_bh(&sta->local->sta_lock);
+}
+
 /* Caller must hold local->sta_lock */
 void sta_info_remove(struct sta_info *sta)
 {
@@ -207,10 +265,9 @@ void sta_info_remove(struct sta_info *sta)
                 sta->flags &= ~WLAN_STA_PS;
                 if (sdata->bss)
                         atomic_dec(&sdata->bss->num_sta_ps);
+                __sta_info_clear_tim_bit(sdata->bss, sta);
         }
         local->num_sta--;
-        sta_info_remove_aid_ptr(sta);
-
 }
 
 void sta_info_free(struct sta_info *sta)
@@ -310,13 +367,8 @@ static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
                        "%s)\n", print_mac(mac, sta->addr));
                 dev_kfree_skb(skb);
 
-                if (skb_queue_empty(&sta->ps_tx_buf)) {
-                        if (sdata->bss)
-                                bss_tim_set(sta->local, sdata->bss, sta->aid);
-                        if (sta->local->ops->set_tim)
-                                sta->local->ops->set_tim(local_to_hw(sta->local),
-                                                         sta->aid, 0);
-                }
+                if (skb_queue_empty(&sta->ps_tx_buf))
+                        sta_info_clear_tim_bit(sta);
         }
 }
 
@@ -395,23 +447,6 @@ void sta_info_stop(struct ieee80211_local *local)
         sta_info_flush(local, NULL);
 }
 
-void sta_info_remove_aid_ptr(struct sta_info *sta)
-{
-        struct ieee80211_sub_if_data *sdata;
-
-        if (sta->aid <= 0)
-                return;
-
-        sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
-
-        if (sdata->bss)
-                __bss_tim_clear(sdata->bss, sta->aid);
-        if (sdata->local->ops->set_tim)
-                sdata->local->ops->set_tim(local_to_hw(sdata->local),
-                                          sta->aid, 0);
-}
-
-
 /**
  * sta_info_flush - flush matching STA entries from the STA table
  * @local: local interface data
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index f3d9f872db4a..4099ece143ef 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -244,7 +244,9 @@ void sta_info_free(struct sta_info *sta);
 void sta_info_init(struct ieee80211_local *local);
 int sta_info_start(struct ieee80211_local *local);
 void sta_info_stop(struct ieee80211_local *local);
-void sta_info_remove_aid_ptr(struct sta_info *sta);
 void sta_info_flush(struct ieee80211_local *local, struct net_device *dev);
 
+void sta_info_set_tim_bit(struct sta_info *sta);
+void sta_info_clear_tim_bit(struct sta_info *sta);
+
 #endif /* STA_INFO_H */
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index db6a871b51ed..69fdb763aa8b 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -416,14 +416,11 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_txrx_data *tx)
                         dev_kfree_skb(old);
                 } else
                         tx->local->total_ps_buffered++;
+
                 /* Queue frame to be sent after STA sends an PS Poll frame */
-                if (skb_queue_empty(&sta->ps_tx_buf)) {
-                        if (tx->sdata->bss)
-                                bss_tim_set(tx->local, tx->sdata->bss, sta->aid);
-                        if (tx->local->ops->set_tim)
-                                tx->local->ops->set_tim(local_to_hw(tx->local),
-                                                       sta->aid, 1);
-                }
+                if (skb_queue_empty(&sta->ps_tx_buf))
+                        sta_info_set_tim_bit(sta);
+
                 pkt_data = (struct ieee80211_tx_packet_data *)tx->skb->cb;
                 pkt_data->jiffies = jiffies;
                 skb_queue_tail(&sta->ps_tx_buf, tx->skb);