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authorJohannes Berg <johannes.berg@intel.com>2013-12-04 22:39:17 +0100
committerJohannes Berg <johannes.berg@intel.com>2013-12-16 11:29:44 +0100
commit6a9d1b91f34df1935bc0ad98114801a44db0f98c (patch)
treeecf4637a32c57786a6ac468be5bc392bb28e779d /net/mac80211
parentc4de673b775e4db48cd2db6277e0c6714332ca0c (diff)
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mac80211: add pre-RCU-sync sta removal driver operation
Currently, mac80211 allows drivers to keep RCU-protected station references that are cleared when the station is removed from the driver and consequently needs to synchronize twice, once before removing the station from the driver (so it can guarantee that the station is no longer used in TX towards the driver) and once after the station is removed from the driver. Add a new pre-RCU-synchronisation station removal operation to the API to allow drivers to clear/invalidate their RCU-protected station pointers before the RCU synchronisation. This will allow removing the second synchronisation by changing the driver API so that the driver may no longer assume a valid RCU-protected pointer after sta_remove/sta_state returns. The alternative to this would be to synchronize_rcu() in all the drivers that currently rely on this behaviour (only iwlmvm) but that would defeat the purpose. Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211')
-rw-r--r--net/mac80211/driver-ops.h16
-rw-r--r--net/mac80211/sta_info.c2
-rw-r--r--net/mac80211/trace.h34
3 files changed, 33 insertions, 19 deletions
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index f98059a45aa5..ef8b385eff04 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -534,6 +534,22 @@ static inline void drv_sta_remove_debugfs(struct ieee80211_local *local,
}
#endif
+static inline void drv_sta_pre_rcu_remove(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ struct sta_info *sta)
+{
+ might_sleep();
+
+ sdata = get_bss_sdata(sdata);
+ check_sdata_in_driver(sdata);
+
+ trace_drv_sta_pre_rcu_remove(local, sdata, &sta->sta);
+ if (local->ops->sta_pre_rcu_remove)
+ local->ops->sta_pre_rcu_remove(&local->hw, &sdata->vif,
+ &sta->sta);
+ trace_drv_return_void(local);
+}
+
static inline __must_check
int drv_sta_state(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 8ae37f60d60c..1e147742eccf 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -873,6 +873,8 @@ int __must_check __sta_info_destroy(struct sta_info *sta)
list_del_rcu(&sta->list);
+ drv_sta_pre_rcu_remove(local, sta->sdata, sta);
+
/* this always calls synchronize_net() */
ieee80211_free_sta_keys(local, sta);
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index 854bc5943127..3a669d7ec7ad 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -766,7 +766,7 @@ TRACE_EVENT(drv_sta_rc_update,
)
);
-TRACE_EVENT(drv_sta_add,
+DECLARE_EVENT_CLASS(sta_event,
TP_PROTO(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta),
@@ -791,29 +791,25 @@ TRACE_EVENT(drv_sta_add,
)
);
-TRACE_EVENT(drv_sta_remove,
+DEFINE_EVENT(sta_event, drv_sta_add,
TP_PROTO(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta),
+ TP_ARGS(local, sdata, sta)
+);
- TP_ARGS(local, sdata, sta),
-
- TP_STRUCT__entry(
- LOCAL_ENTRY
- VIF_ENTRY
- STA_ENTRY
- ),
-
- TP_fast_assign(
- LOCAL_ASSIGN;
- VIF_ASSIGN;
- STA_ASSIGN;
- ),
+DEFINE_EVENT(sta_event, drv_sta_remove,
+ TP_PROTO(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_sta *sta),
+ TP_ARGS(local, sdata, sta)
+);
- TP_printk(
- LOCAL_PR_FMT VIF_PR_FMT STA_PR_FMT,
- LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG
- )
+DEFINE_EVENT(sta_event, drv_sta_pre_rcu_remove,
+ TP_PROTO(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_sta *sta),
+ TP_ARGS(local, sdata, sta)
);
TRACE_EVENT(drv_conf_tx,