From 10d78f278214bd7c8a15d09ce2304728114786e7 Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Thu, 5 Jun 2014 14:21:37 +0200 Subject: [PATCH] mac80211: use csa counter offsets instead of csa_active vif->csa_active is protected by mutexes only. This means it is unreliable to depend on it on codeflow in non-sleepable beacon and CSA code. There was no guarantee to have vif->csa_active update be visible before beacons are updated on SMP systems. Using csa counter offsets which are embedded in beacon struct (and thus are protected with single RCU assignment) is much safer. Signed-off-by: Michal Kazior Signed-off-by: Johannes Berg --- net/mac80211/tx.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index ed56f0091663..d741b7369dc4 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -2538,6 +2538,9 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif) goto out; } + if (!beacon->csa_counter_offsets[0]) + goto out; + if (WARN_ON_ONCE(beacon->csa_counter_offsets[0] > beacon_data_len)) goto out; @@ -2582,7 +2585,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw, beacon = rcu_dereference(ap->beacon); if (beacon) { - if (sdata->vif.csa_active) { + if (beacon->csa_counter_offsets[0]) { if (!is_template) ieee80211_csa_update_counter(vif); @@ -2628,7 +2631,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw, if (!beacon) goto out; - if (sdata->vif.csa_active) { + if (beacon->csa_counter_offsets[0]) { if (!is_template) ieee80211_csa_update_counter(vif); @@ -2653,7 +2656,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw, if (!beacon) goto out; - if (sdata->vif.csa_active) { + if (beacon->csa_counter_offsets[0]) { if (!is_template) /* TODO: For mesh csa_counter is in TU, so * decrementing it by one isn't correct, but -- 2.20.1