From 1f4ac5a63f897a480fffd0d5c843b03f02c384a5 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 8 Feb 2013 12:07:44 +0100 Subject: [PATCH] mac80211: explicitly copy channels to VLANs where needed Currently the code assigns channel contexts to VLANs (for use by the TX/RX code) when the AP master gets its channel context assigned. This works fine, but in the upcoming radar detection work the VLANs don't require a channel context (during radar detection) and assigning one to them anyway causes issues with locking and also inconsistencies -- a VLAN interface that is added before radar detection would get the channel context, while one added during it wouldn't. Fix these issues moving the channel context copying to a new explicit operation that will not be used in the radar detection code. Acked-by: Simon Wunderlich Signed-off-by: Johannes Berg --- net/mac80211/cfg.c | 2 ++ net/mac80211/chan.c | 52 +++++++++++++++++++++++++------------- net/mac80211/ieee80211_i.h | 2 ++ 3 files changed, 38 insertions(+), 18 deletions(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index f4f7e7691077..8f6b593a921f 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -933,6 +933,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev, IEEE80211_CHANCTX_SHARED); if (err) return err; + ieee80211_vif_copy_chanctx_to_vlans(sdata, false); /* * Apply control port protocol, this allows us to @@ -1047,6 +1048,7 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev) local->total_ps_buffered -= skb_queue_len(&sdata->u.ap.ps.bc_buf); skb_queue_purge(&sdata->u.ap.ps.bc_buf); + ieee80211_vif_copy_chanctx_to_vlans(sdata, true); ieee80211_vif_release_channel(sdata); return 0; diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 1bfe0a8b19d2..b5b50762f03e 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -198,15 +198,6 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata) ctx = container_of(conf, struct ieee80211_chanctx, conf); - if (sdata->vif.type == NL80211_IFTYPE_AP) { - struct ieee80211_sub_if_data *vlan; - - /* for the VLAN list */ - ASSERT_RTNL(); - list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) - rcu_assign_pointer(vlan->vif.chanctx_conf, NULL); - } - ieee80211_unassign_vif_chanctx(sdata, ctx); if (ctx->refcount == 0) ieee80211_free_chanctx(local, ctx); @@ -326,15 +317,6 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata, goto out; } - if (sdata->vif.type == NL80211_IFTYPE_AP) { - struct ieee80211_sub_if_data *vlan; - - /* for the VLAN list */ - ASSERT_RTNL(); - list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) - rcu_assign_pointer(vlan->vif.chanctx_conf, &ctx->conf); - } - ieee80211_recalc_smps_chanctx(local, ctx); out: mutex_unlock(&local->chanctx_mtx); @@ -369,6 +351,40 @@ void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata) mutex_unlock(&local->chanctx_mtx); } +void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata, + bool clear) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_sub_if_data *vlan; + struct ieee80211_chanctx_conf *conf; + + ASSERT_RTNL(); + + if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP)) + return; + + mutex_lock(&local->chanctx_mtx); + + /* + * Check that conf exists, even when clearing this function + * must be called with the AP's channel context still there + * as it would otherwise cause VLANs to have an invalid + * channel context pointer for a while, possibly pointing + * to a channel context that has already been freed. + */ + conf = rcu_dereference_protected(sdata->vif.chanctx_conf, + lockdep_is_held(&local->chanctx_mtx)); + WARN_ON(!conf); + + if (clear) + conf = NULL; + + list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) + rcu_assign_pointer(vlan->vif.chanctx_conf, conf); + + mutex_unlock(&local->chanctx_mtx); +} + void ieee80211_iter_chan_contexts_atomic( struct ieee80211_hw *hw, void (*iter)(struct ieee80211_hw *hw, diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 080cf0942ce7..8e884fcbe79b 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1605,6 +1605,8 @@ ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata, enum ieee80211_chanctx_mode mode); void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata); void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata); +void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata, + bool clear); void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local, struct ieee80211_chanctx *chanctx);