From e996ec2a4ddb53164262990d33304c429709f687 Mon Sep 17 00:00:00 2001 From: Wojciech Dubowik Date: Wed, 10 Jun 2015 13:06:53 +0200 Subject: [PATCH] mac80211: avoid unnecessary beacon deref on CSA counter update The beacon struct is already available in many contexts that are also already in an RCU read-locked section. Avoid that by using the existing beacon struct pointer directly. Signed-off-by: Wojciech Dubowik [rewrite subject/add commit message] Signed-off-by: Johannes Berg --- net/mac80211/tx.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 87b9b4e27d22..7c6832f91dc3 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3210,6 +3210,16 @@ static void ieee80211_set_csa(struct ieee80211_sub_if_data *sdata, rcu_read_unlock(); } +static u8 __ieee80211_csa_update_counter(struct beacon_data *beacon) +{ + beacon->csa_current_counter--; + + /* the counter should never reach 0 */ + WARN_ON_ONCE(!beacon->csa_current_counter); + + return beacon->csa_current_counter; +} + u8 ieee80211_csa_update_counter(struct ieee80211_vif *vif) { struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif); @@ -3228,11 +3238,7 @@ u8 ieee80211_csa_update_counter(struct ieee80211_vif *vif) if (!beacon) goto unlock; - beacon->csa_current_counter--; - - /* the counter should never reach 0 */ - WARN_ON_ONCE(!beacon->csa_current_counter); - count = beacon->csa_current_counter; + count = __ieee80211_csa_update_counter(beacon); unlock: rcu_read_unlock(); @@ -3332,7 +3338,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw, if (beacon) { if (beacon->csa_counter_offsets[0]) { if (!is_template) - ieee80211_csa_update_counter(vif); + __ieee80211_csa_update_counter(beacon); ieee80211_set_csa(sdata, beacon); } @@ -3378,7 +3384,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw, if (beacon->csa_counter_offsets[0]) { if (!is_template) - ieee80211_csa_update_counter(vif); + __ieee80211_csa_update_counter(beacon); ieee80211_set_csa(sdata, beacon); } @@ -3408,7 +3414,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw, * for now we leave it consistent with overall * mac80211's behavior. */ - ieee80211_csa_update_counter(vif); + __ieee80211_csa_update_counter(beacon); ieee80211_set_csa(sdata, beacon); } -- 2.20.1