| From | Greg Kroah-Hartman <> | Subject | [ 020/115] mac80211: use synchronize_rcu() with rcu_barrier() | Date | Mon, 6 May 2013 13:44:16 -0700 |
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3.9-stable review patch. If anyone has any objections, please let me know.
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From: Bob Copeland <me@bobcopeland.com>
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@cozybit.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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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