mac80211: delay IBSS station insertion

In order to notify drivers and simplify the station
management code, defer IBSS station insertion to a
work item and don't do it directly while receiving
a frame.

This increases the complexity in IBSS a little bit,
but it's pretty straight forward and it allows us
to reduce the station management complexity (next
patch) considerably.

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

4 files changed, 140 insertions, 57 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 47e2db9133cb..f8a32bf98216 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -275,6 +275,80 @@ static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
                                   cbss->tsf);
 }
 
+static struct sta_info *ieee80211_ibss_finish_sta(struct sta_info *sta)
+        __acquires(RCU)
+{
+        struct ieee80211_sub_if_data *sdata = sta->sdata;
+        u8 addr[ETH_ALEN];
+
+        memcpy(addr, sta->sta.addr, ETH_ALEN);
+
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+        wiphy_debug(sdata->local->hw.wiphy,
+                    "Adding new IBSS station %pM (dev=%s)\n",
+                    addr, sdata->name);
+#endif
+
+        sta_info_move_state(sta, IEEE80211_STA_AUTH);
+        sta_info_move_state(sta, IEEE80211_STA_ASSOC);
+        sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
+
+        rate_control_rate_init(sta);
+
+        /* If it fails, maybe we raced another insertion? */
+        if (sta_info_insert_rcu(sta))
+                return sta_info_get(sdata, addr);
+        return sta;
+}
+
+static struct sta_info *
+ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
+                       const u8 *bssid, const u8 *addr,
+                       u32 supp_rates)
+        __acquires(RCU)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct ieee80211_local *local = sdata->local;
+        struct sta_info *sta;
+        int band = local->hw.conf.channel->band;
+
+        /*
+         * XXX: Consider removing the least recently used entry and
+         *      allow new one to be added.
+         */
+        if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
+                if (net_ratelimit())
+                        printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
+                               sdata->name, addr);
+                rcu_read_lock();
+                return NULL;
+        }
+
+        if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH) {
+                rcu_read_lock();
+                return NULL;
+        }
+
+        if (compare_ether_addr(bssid, sdata->u.ibss.bssid)) {
+                rcu_read_lock();
+                return NULL;
+        }
+
+        sta = sta_info_alloc(sdata, addr, GFP_KERNEL);
+        if (!sta) {
+                rcu_read_lock();
+                return NULL;
+        }
+
+        sta->last_rx = jiffies;
+
+        /* make sure mandatory rates are always added */
+        sta->sta.supp_rates[band] = supp_rates |
+                        ieee80211_mandatory_rates(local, band);
+
+        return ieee80211_ibss_finish_sta(sta);
+}
+
 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
                                   struct ieee80211_mgmt *mgmt,
                                   size_t len,
@@ -334,10 +408,11 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 #endif
                                         rates_updated = true;
                                 }
-                        } else
+                        } else {
+                                rcu_read_unlock();
                                 sta = ieee80211_ibss_add_sta(sdata, mgmt->bssid,
-                                                mgmt->sa, supp_rates,
-                                                GFP_ATOMIC);
+                                                mgmt->sa, supp_rates);
+                        }
                 }
 
                 if (sta && elems->wmm_info)
@@ -464,21 +539,17 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
                 ieee80211_sta_join_ibss(sdata, bss);
                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
-                                       supp_rates, GFP_KERNEL);
+                                       supp_rates);
+                rcu_read_unlock();
         }
 
  put_bss:
         ieee80211_rx_bss_put(local, bss);
 }
 
-/*
- * Add a new IBSS station, will also be called by the RX code when,
- * in IBSS mode, receiving a frame from a yet-unknown station, hence
- * must be callable in atomic context.
- */
-struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
-                                        u8 *bssid, u8 *addr, u32 supp_rates,
-                                        gfp_t gfp)
+void ieee80211_ibss_rx_no_sta(struct ieee80211_sub_if_data *sdata,
+                              const u8 *bssid, const u8 *addr,
+                              u32 supp_rates)
 {
         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
         struct ieee80211_local *local = sdata->local;
@@ -493,40 +564,29 @@ struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
                 if (net_ratelimit())
                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
                                sdata->name, addr);
-                return NULL;
+                return;
         }
 
         if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
-                return NULL;
+                return;
 
         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
-                return NULL;
-
-#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
-        wiphy_debug(local->hw.wiphy, "Adding new IBSS station %pM (dev=%s)\n",
-                    addr, sdata->name);
-#endif
+                return;
 
-        sta = sta_info_alloc(sdata, addr, gfp);
+        sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
         if (!sta)
-                return NULL;
+                return;
 
         sta->last_rx = jiffies;
 
-        sta_info_move_state(sta, IEEE80211_STA_AUTH);
-        sta_info_move_state(sta, IEEE80211_STA_ASSOC);
-        sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
-
         /* make sure mandatory rates are always added */
         sta->sta.supp_rates[band] = supp_rates |
                         ieee80211_mandatory_rates(local, band);
 
-        rate_control_rate_init(sta);
-
-        /* If it fails, maybe we raced another insertion? */
-        if (sta_info_insert(sta))
-                return sta_info_get(sdata, addr);
-        return sta;
+        spin_lock(&ifibss->incomplete_lock);
+        list_add(&sta->list, &ifibss->incomplete_stations);
+        spin_unlock(&ifibss->incomplete_lock);
+        ieee80211_queue_work(&local->hw, &sdata->work);
 }
 
 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
@@ -865,6 +925,7 @@ void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
 {
         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct sta_info *sta;
 
         mutex_lock(&ifibss->mtx);
 
@@ -876,6 +937,19 @@ void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
         if (!ifibss->ssid_len)
                 goto out;
 
+        spin_lock_bh(&ifibss->incomplete_lock);
+        while (!list_empty(&ifibss->incomplete_stations)) {
+                sta = list_first_entry(&ifibss->incomplete_stations,
+                                       struct sta_info, list);
+                list_del(&sta->list);
+                spin_unlock_bh(&ifibss->incomplete_lock);
+
+                ieee80211_ibss_finish_sta(sta);
+                rcu_read_unlock();
+                spin_lock_bh(&ifibss->incomplete_lock);
+        }
+        spin_unlock_bh(&ifibss->incomplete_lock);
+
         switch (ifibss->state) {
         case IEEE80211_IBSS_MLME_SEARCH:
                 ieee80211_sta_find_ibss(sdata);
@@ -934,6 +1008,8 @@ void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
                     (unsigned long) sdata);
         mutex_init(&ifibss->mtx);
+        INIT_LIST_HEAD(&ifibss->incomplete_stations);
+        spin_lock_init(&ifibss->incomplete_lock);
 }
 
 /* scan finished notification */
@@ -1053,6 +1129,7 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
         struct cfg80211_bss *cbss;
         u16 capability;
         int active_ibss;
+        struct sta_info *sta;
 
         mutex_lock(&sdata->u.ibss.mtx);
 
@@ -1081,6 +1158,19 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
         }
 
         sta_info_flush(sdata->local, sdata);
+
+        spin_lock_bh(&ifibss->incomplete_lock);
+        while (!list_empty(&ifibss->incomplete_stations)) {
+                sta = list_first_entry(&ifibss->incomplete_stations,
+                                       struct sta_info, list);
+                list_del(&sta->list);
+                spin_unlock_bh(&ifibss->incomplete_lock);
+
+                sta_info_free(local, sta);
+                spin_lock_bh(&ifibss->incomplete_lock);
+        }
+        spin_unlock_bh(&ifibss->incomplete_lock);
+
         netif_carrier_off(sdata->dev);
 
         /* remove beacon */
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9516c3088fba..eca6063e287c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -482,6 +482,9 @@ struct ieee80211_if_ibss {
         struct sk_buff __rcu *presp;
         struct sk_buff *skb;
 
+        spinlock_t incomplete_lock;
+        struct list_head incomplete_stations;
+
         enum {
                 IEEE80211_IBSS_MLME_SEARCH,
                 IEEE80211_IBSS_MLME_JOINED,
@@ -1172,9 +1175,8 @@ void ieee80211_sta_reset_conn_monitor(struct ieee80211_sub_if_data *sdata);
 /* IBSS code */
 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local);
 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata);
-struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
-                                        u8 *bssid, u8 *addr, u32 supp_rates,
-                                        gfp_t gfp);
+void ieee80211_ibss_rx_no_sta(struct ieee80211_sub_if_data *sdata,
+                              const u8 *bssid, const u8 *addr, u32 supp_rates);
 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
                         struct cfg80211_ibss_params *params);
 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata);
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 7d226417ef46..2be5b7d69ad7 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2775,8 +2775,8 @@ static int prepare_for_handlers(struct ieee80211_rx_data *rx,
                                 rate_idx = 0; /* TODO: HT rates */
                         else
                                 rate_idx = status->rate_idx;
-                        rx->sta = ieee80211_ibss_add_sta(sdata, bssid,
-                                        hdr->addr2, BIT(rate_idx), GFP_ATOMIC);
+                        ieee80211_ibss_rx_no_sta(sdata, bssid, hdr->addr2,
+                                                 BIT(rate_idx));
                 }
                 break;
         case NL80211_IFTYPE_MESH_POINT:
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 16de3bd16107..aa9293d7f3f0 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -354,35 +354,26 @@ static int sta_info_finish_insert(struct sta_info *sta,
                 /* notify driver */
                 err = drv_sta_add(local, sdata, &sta->sta);
                 if (err) {
-                        if (!async)
+                        if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
                                 return err;
                         printk(KERN_DEBUG "%s: failed to add IBSS STA %pM to "
                                           "driver (%d) - keeping it anyway.\n",
                                sdata->name, sta->sta.addr, err);
-                } else {
+                } else
                         sta->uploaded = true;
-#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
-                        if (async)
-                                wiphy_debug(local->hw.wiphy,
-                                            "Finished adding IBSS STA %pM\n",
-                                            sta->sta.addr);
-#endif
-                }
 
                 sdata = sta->sdata;
         }
 
         if (!dummy_reinsert) {
-                if (!async) {
-                        local->num_sta++;
-                        local->sta_generation++;
-                        smp_mb();
-
-                        /* make the station visible */
-                        spin_lock_irqsave(&local->sta_lock, flags);
-                        sta_info_hash_add(local, sta);
-                        spin_unlock_irqrestore(&local->sta_lock, flags);
-                }
+                local->num_sta++;
+                local->sta_generation++;
+                smp_mb();
+
+                /* make the station visible */
+                spin_lock_irqsave(&local->sta_lock, flags);
+                sta_info_hash_add(local, sta);
+                spin_unlock_irqrestore(&local->sta_lock, flags);
 
                 list_add(&sta->list, &local->sta_list);
         } else {
@@ -1546,7 +1537,7 @@ EXPORT_SYMBOL(ieee80211_sta_set_buffered);
 int sta_info_move_state_checked(struct sta_info *sta,
                                 enum ieee80211_sta_state new_state)
 {
-        /* might_sleep(); -- for driver notify later, fix IBSS first */
+        might_sleep();
 
         if (sta->sta_state == new_state)
                 return 0;