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mac80211: use synchronize_rcu() with rcu_barrier()

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The RCU docs used to state that rcu_barrier() included a wait
for an RCU grace period; however the comments for rcu_barrier()
as of commit f0a0e6f... "rcu: Clarify memory-ordering properties
of grace-period primitives" contradict this.

So add back synchronize_{rcu,net}() to where they once were,
but keep the rcu_barrier()s for the call_rcu() callbacks.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bob Copeland <bob@cozybit.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Bob Copeland 2013-04-18 18:26:49 -04:00 committed by Johannes Berg
parent 908f8d07e9
commit 8ceb59557b
3 changed files with 5 additions and 2 deletions
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1
net/mac80211/cfg.c
View file

@ -1043,6 +1043,7 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev)
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
sta_info_flush_defer(vlan);
sta_info_flush_defer(sdata);
synchronize_net();
rcu_barrier();
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
sta_info_flush_cleanup(vlan);

5
net/mac80211/iface.c
View file

@ -839,11 +839,12 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
*
* sta_info_flush_cleanup() requires rcu_barrier()
* first to wait for the station call_rcu() calls
* to complete, here we need at least sychronize_rcu()
* it to wait for the RX path in case it is using the
* to complete, and we also need synchronize_rcu()
* 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();
rcu_barrier();
sta_info_flush_cleanup(sdata);

1
net/mac80211/pm.c
View file

@ -38,6 +38,7 @@ int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
IEEE80211_QUEUE_STOP_REASON_SUSPEND);
/* flush out all packets and station cleanup call_rcu()s */
synchronize_net();
rcu_barrier();
ieee80211_flush_queues(local, NULL);