3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bob Copeland <me@xxxxxxxxxxxxxxx>
commit 8ceb59557bdc373e532b87d4142ce27e04218f0e upstream.
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.
Signed-off-by: Bob Copeland <bob@xxxxxxxxxxx>
Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mac80211/cfg.c | 1 +
net/mac80211/iface.c | 5 +++--
net/mac80211/pm.c | 1 +
3 files changed, 5 insertions(+), 2 deletions(-)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1034,6 +1034,7 @@ static int ieee80211_stop_ap(struct wiph
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);
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -844,11 +844,12 @@ static void ieee80211_do_stop(struct iee
*
* 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);
--- a/net/mac80211/pm.c
+++ b/net/mac80211/pm.c
@@ -54,6 +54,7 @@ int __ieee80211_suspend(struct ieee80211
IEEE80211_QUEUE_STOP_REASON_SUSPEND);
/* flush out all packets and station cleanup call_rcu()s */
+ synchronize_net();
rcu_barrier();
drv_flush(local, false);
--
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