From 4a199068230bd8074f2e39025a2216390ea5b829 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 26 Apr 2017 10:58:53 +0300 Subject: [PATCH] mac80211: disentangle iflist_mtx and chanctx_mtx At least on iwlwifi, sometimes lockdep complains that we can lock chanctx_mtx -> mvm.mutex -> iflist_mtx (due to iterate_interfaces) and iflist_mtx -> chanctx_mtx Remove the latter dependency in mac80211 by using the RTNL that we already hold in one case, and can relatively easily achieve in the other case. Signed-off-by: Johannes Berg --- net/mac80211/cfg.c | 6 +----- net/mac80211/main.c | 2 ++ net/mac80211/util.c | 9 ++++++--- 3 files changed, 9 insertions(+), 8 deletions(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 038c31336167..e4a370b42a93 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -739,11 +739,8 @@ static int ieee80211_set_monitor_channel(struct wiphy *wiphy, return 0; mutex_lock(&local->mtx); - mutex_lock(&local->iflist_mtx); if (local->use_chanctx) { - sdata = rcu_dereference_protected( - local->monitor_sdata, - lockdep_is_held(&local->iflist_mtx)); + sdata = rtnl_dereference(local->monitor_sdata); if (sdata) { ieee80211_vif_release_channel(sdata); ret = ieee80211_vif_use_channel(sdata, chandef, @@ -756,7 +753,6 @@ static int ieee80211_set_monitor_channel(struct wiphy *wiphy, if (ret == 0) local->monitor_chandef = *chandef; - mutex_unlock(&local->iflist_mtx); mutex_unlock(&local->mtx); return ret; diff --git a/net/mac80211/main.c b/net/mac80211/main.c index ae408a96c407..8aa1f5b6a051 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -253,6 +253,7 @@ static void ieee80211_restart_work(struct work_struct *work) WARN(test_bit(SCAN_HW_SCANNING, &local->scanning), "%s called with hardware scan in progress\n", __func__); + flush_work(&local->radar_detected_work); rtnl_lock(); list_for_each_entry(sdata, &local->interfaces, list) flush_delayed_work(&sdata->dec_tailroom_needed_wk); @@ -1187,6 +1188,7 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw) cancel_work_sync(&local->reconfig_filter); cancel_work_sync(&local->tdls_chsw_work); flush_work(&local->sched_scan_stopped_work); + flush_work(&local->radar_detected_work); ieee80211_clear_tx_pending(local); rate_control_deinitialize(local); diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 7a37ce78bb38..37dad3dd6bac 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -2791,8 +2791,10 @@ void ieee80211_dfs_cac_cancel(struct ieee80211_local *local) struct ieee80211_sub_if_data *sdata; struct cfg80211_chan_def chandef; + /* for interface list, to avoid linking iflist_mtx and chanctx_mtx */ + ASSERT_RTNL(); + mutex_lock(&local->mtx); - mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { /* it might be waiting for the local->mtx, but then * by the time it gets it, sdata->wdev.cac_started @@ -2809,7 +2811,6 @@ void ieee80211_dfs_cac_cancel(struct ieee80211_local *local) GFP_KERNEL); } } - mutex_unlock(&local->iflist_mtx); mutex_unlock(&local->mtx); } @@ -2831,7 +2832,9 @@ void ieee80211_dfs_radar_detected_work(struct work_struct *work) } mutex_unlock(&local->chanctx_mtx); + rtnl_lock(); ieee80211_dfs_cac_cancel(local); + rtnl_unlock(); if (num_chanctx > 1) /* XXX: multi-channel is not supported yet */ @@ -2846,7 +2849,7 @@ void ieee80211_radar_detected(struct ieee80211_hw *hw) trace_api_radar_detected(local); - ieee80211_queue_work(hw, &local->radar_detected_work); + schedule_work(&local->radar_detected_work); } EXPORT_SYMBOL(ieee80211_radar_detected); -- 2.45.2