From: Johannes Berg Date: Thu, 13 Dec 2012 22:49:02 +0000 (+0100) Subject: mac80211: optimise roaming time again X-Git-Tag: v3.9-rc1~139^2~242^2^2~158 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=051007d9e281cd8ea603a4cc4c96b0170b26c7e9;p=platform%2Fkernel%2Flinux-stable.git mac80211: optimise roaming time again The last fixes re-added the RCU synchronize penalty on roaming to fix the races. Split up sta_info_flush() now to get rid of that again, and let managed mode (and only it) delay the actual destruction. Tested-by: Ben Greear Signed-off-by: Johannes Berg --- diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 604b4aa..12341ef 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -775,8 +775,10 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, * This is relevant only in WDS mode, in all other modes we've * already removed all stations when disconnecting or similar, * so warn otherwise. + * + * We call sta_info_flush_cleanup() later, to combine RCU waits. */ - flushed = sta_info_flush(sdata); + flushed = sta_info_flush_defer(sdata); WARN_ON_ONCE((sdata->vif.type != NL80211_IFTYPE_WDS && flushed > 0) || (sdata->vif.type == NL80211_IFTYPE_WDS && flushed != 1)); @@ -861,11 +863,14 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, cancel_work_sync(&sdata->work); /* * When we get here, the interface is marked down. - * Call synchronize_rcu() to wait for the RX path - * should it be using the interface and enqueuing - * frames at this very time on another CPU. + * sta_info_flush_cleanup() calls rcu_barrier to + * wait for the station call_rcu() calls to complete, + * here we require it to wait for the RX path in case + * it is using the interface and enqueuing frames at + * this very time on another CPU. */ - synchronize_rcu(); + sta_info_flush_cleanup(sdata); + skb_queue_purge(&sdata->skb_queue); /* diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 6d61d2f..3cf85d8 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1521,7 +1521,7 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata, memset(ifmgd->bssid, 0, ETH_ALEN); /* remove AP and TDLS peers */ - sta_info_flush(sdata); + sta_info_flush_defer(sdata); /* finally reset all BSS / config parameters */ changed |= ieee80211_reset_erp_info(sdata); diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index d743645..7199b9d 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -104,6 +104,16 @@ static void cleanup_single_sta(struct sta_info *sta) * neither mac80211 nor the driver can reference this * sta struct any more except by still existing timers * associated with this station that we clean up below. + * + * Note though that this still uses the sdata and even + * calls the driver in AP and mesh mode, so interfaces + * of those types mush use call sta_info_flush_cleanup() + * (typically via sta_info_flush()) before deconfiguring + * the driver. + * + * In station mode, nothing happens here so it doesn't + * have to (and doesn't) do that, this is intentional to + * speed up roaming. */ if (test_sta_flag(sta, WLAN_STA_PS_STA)) { @@ -887,14 +897,8 @@ void sta_info_stop(struct ieee80211_local *local) del_timer_sync(&local->sta_cleanup); } -/** - * sta_info_flush - flush matching STA entries from the STA table - * - * Returns the number of removed STA entries. - * - * @sdata: sdata to remove all stations from - */ -int sta_info_flush(struct ieee80211_sub_if_data *sdata) + +int sta_info_flush_defer(struct ieee80211_sub_if_data *sdata) { struct ieee80211_local *local = sdata->local; struct sta_info *sta, *tmp; @@ -911,12 +915,15 @@ int sta_info_flush(struct ieee80211_sub_if_data *sdata) } mutex_unlock(&local->sta_mtx); + return ret; +} + +void sta_info_flush_cleanup(struct ieee80211_sub_if_data *sdata) +{ rcu_barrier(); ieee80211_cleanup_sdata_stas(sdata); cancel_work_sync(&sdata->cleanup_stations_wk); - - return ret; } void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata, diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 13698da..c3266aed 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -548,7 +548,25 @@ void sta_info_recalc_tim(struct sta_info *sta); void sta_info_init(struct ieee80211_local *local); void sta_info_stop(struct ieee80211_local *local); -int sta_info_flush(struct ieee80211_sub_if_data *sdata); +int sta_info_flush_defer(struct ieee80211_sub_if_data *sdata); +void sta_info_flush_cleanup(struct ieee80211_sub_if_data *sdata); + +/** + * sta_info_flush - flush matching STA entries from the STA table + * + * Returns the number of removed STA entries. + * + * @sdata: sdata to remove all stations from + */ +static inline int sta_info_flush(struct ieee80211_sub_if_data *sdata) +{ + int ret = sta_info_flush_defer(sdata); + + sta_info_flush_cleanup(sdata); + + return ret; +} + void sta_set_rate_info_tx(struct sta_info *sta, const struct ieee80211_tx_rate *rate, struct rate_info *rinfo);