From 73651ee6396c499ccb59ebc84c9274db01ed026d Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 25 Feb 2008 16:27:47 +0100 Subject: mac80211: split sta_info_add sta_info_add() has two functions: allocating a station info structure and inserting it into the hash table/list. Splitting these two functions allows allocating with GFP_KERNEL in many places instead of GFP_ATOMIC which is now required by the RCU protection. Additionally, in many places RCU protection is now no longer needed at all because between sta_info_alloc() and sta_info_insert() the caller owns the structure. This fixes a few race conditions with setting initial flags and similar, but not all (see comments in ieee80211_sta.c and cfg.c). More documentation on the existing races will be in a follow-up patch. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/cfg.c | 42 +++++++++++++++++++++++++++++++++--------- 1 file changed, 33 insertions(+), 9 deletions(-) (limited to 'net/mac80211/cfg.c') diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index e9ba6fcc0e45..6263cfc148c0 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -571,6 +571,12 @@ static void sta_apply_parameters(struct ieee80211_local *local, struct ieee80211_supported_band *sband; struct ieee80211_sub_if_data *sdata = sta->sdata; + /* + * FIXME: updating the flags is racy when this function is + * called from ieee80211_change_station(), this will + * be resolved in a future patch. + */ + if (params->station_flags & STATION_FLAG_CHANGED) { sta->flags &= ~WLAN_STA_AUTHORIZED; if (params->station_flags & STATION_FLAG_AUTHORIZED) @@ -585,6 +591,13 @@ static void sta_apply_parameters(struct ieee80211_local *local, sta->flags |= WLAN_STA_WME; } + /* + * FIXME: updating the following information is racy when this + * function is called from ieee80211_change_station(). + * However, all this information should be static so + * maybe we should just reject attemps to change it. + */ + if (params->aid) { sta->aid = params->aid; if (sta->aid > IEEE80211_MAX_AID) @@ -626,6 +639,7 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev, struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr); struct sta_info *sta; struct ieee80211_sub_if_data *sdata; + int err; /* Prevent a race with changing the rate control algorithm */ if (!netif_running(dev)) @@ -641,16 +655,11 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev, sdata = IEEE80211_DEV_TO_SUB_IF(dev); if (ieee80211_vif_is_mesh(&sdata->vif)) - sta = mesh_plink_add(mac, DEFAULT_RATES, sdata); + sta = mesh_plink_alloc(sdata, mac, DEFAULT_RATES, GFP_KERNEL); else - sta = sta_info_add(sdata, mac); - - if (IS_ERR(sta)) - return PTR_ERR(sta); - - if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN || - sdata->vif.type == IEEE80211_IF_TYPE_AP) - ieee80211_send_layer2_update(sta); + sta = sta_info_alloc(sdata, mac, GFP_KERNEL); + if (!sta) + return -ENOMEM; sta->flags = WLAN_STA_AUTH | WLAN_STA_ASSOC; @@ -658,6 +667,21 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev, rate_control_rate_init(sta, local); + rcu_read_lock(); + + err = sta_info_insert(sta); + if (err) { + sta_info_destroy(sta); + rcu_read_unlock(); + return err; + } + + if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN || + sdata->vif.type == IEEE80211_IF_TYPE_AP) + ieee80211_send_layer2_update(sta); + + rcu_read_unlock(); + return 0; } -- cgit v1.2.1