From: Antonio Quartulli <antonio@xxxxxxxxxxxxx>
I need to invoke ieee80211_iter_keys() from a periodic worker in a driver and
therefore I would prefer to get rid of any of locks to avoid problems.
These two patches try to use rcu lock to protect the iteration, but I'd like to
get a feedback before sending this stuff as a patch :-)
Moreover, why do we use list_for_each_entry_safe() is ieee80211_iter_keys() if
the list cannot be altered (pointer to key is not passed to iter() so we should
be sure that nobody is going to invoke list_del())?
Cheers,
In ieee80211_iter_keys the local->interfaces list is
accessed for reading only. RCU can be used instead
of pretending to be under RTNL lock.
This can simplify future users of this function.
Signed-off-by: Antonio Quartulli <antonio@xxxxxxxxxxxxx>
---
net/mac80211/key.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 3e51dd7..04c885a 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -550,8 +550,6 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw,
struct ieee80211_key *key, *tmp;
struct ieee80211_sub_if_data *sdata;
- ASSERT_RTNL();
-
mutex_lock(&local->key_mtx);
if (vif) {
sdata = vif_to_sdata(vif);
@@ -560,12 +558,14 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw,
key->sta ? &key->sta->sta : NULL,
&key->conf, iter_data);
} else {
- list_for_each_entry(sdata, &local->interfaces, list)
+ rcu_read_lock();
+ list_for_each_entry_rcu(sdata, &local->interfaces, list)
list_for_each_entry_safe(key, tmp,
&sdata->key_list, list)
iter(hw, &sdata->vif,
key->sta ? &key->sta->sta : NULL,
&key->conf, iter_data);
+ rcu_read_unlock();
}
mutex_unlock(&local->key_mtx);
}
--
1.8.5.1
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