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iwlwifi: mvm: don't leak a station when we drain

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We had a bug that prevented us from removing a station
after we entered the drain flow:

We assign sta to be NULL if it was an error value.
Then we tested it against -EBUSY, but forget to retrieve
the value again from mvm->fw_id_to_mac_id[sta_id].

Due to this bug, we ended up never removing the STA from
the firmware. This led to an firmware assert when we remove
the GO vif.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
This commit is contained in:
Emmanuel Grumbach 2014-01-20 15:21:26 +02:00
parent 6e0bbe5ee8
commit 9bb0c1adc5
1 changed files with 37 additions and 36 deletions
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73
drivers/net/wireless/iwlwifi/mvm/tx.c
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@ -659,8 +659,14 @@ static void iwl_mvm_rx_tx_cmd_single(struct iwl_mvm *mvm,
rcu_read_lock();
sta = rcu_dereference(mvm->fw_id_to_mac_id[sta_id]);
/*
* sta can't be NULL otherwise it'd mean that the sta has been freed in
* the firmware while we still have packets for it in the Tx queues.
*/
if (WARN_ON_ONCE(!sta))
goto out;
if (!IS_ERR_OR_NULL(sta)) {
if (!IS_ERR(sta)) {
mvmsta = iwl_mvm_sta_from_mac80211(sta);
if (tid != IWL_TID_NON_QOS) {
@ -675,7 +681,6 @@ static void iwl_mvm_rx_tx_cmd_single(struct iwl_mvm *mvm,
spin_unlock_bh(&mvmsta->lock);
}
} else {
sta = NULL;
mvmsta = NULL;
}
@ -683,42 +688,38 @@ static void iwl_mvm_rx_tx_cmd_single(struct iwl_mvm *mvm,
* If the txq is not an AMPDU queue, there is no chance we freed
* several skbs. Check that out...
*/
if (txq_id < mvm->first_agg_queue && !WARN_ON(skb_freed > 1) &&
atomic_sub_and_test(skb_freed, &mvm->pending_frames[sta_id])) {
if (mvmsta) {
/*
* If there are no pending frames for this STA, notify
* mac80211 that this station can go to sleep in its
* STA table.
*/
if (mvmsta->vif->type == NL80211_IFTYPE_AP)
ieee80211_sta_block_awake(mvm->hw, sta, false);
/*
* We might very well have taken mvmsta pointer while
* the station was being removed. The remove flow might
* have seen a pending_frame (because we didn't take
* the lock) even if now the queues are drained. So make
* really sure now that this the station is not being
* removed. If it is, run the drain worker to remove it.
*/
spin_lock_bh(&mvmsta->lock);
sta = rcu_dereference(mvm->fw_id_to_mac_id[sta_id]);
if (!sta || PTR_ERR(sta) == -EBUSY) {
/*
* Station disappeared in the meantime:
* so we are draining.
*/
set_bit(sta_id, mvm->sta_drained);
schedule_work(&mvm->sta_drained_wk);
}
spin_unlock_bh(&mvmsta->lock);
} else if (!mvmsta && PTR_ERR(sta) == -EBUSY) {
/* Tx response without STA, so we are draining */
set_bit(sta_id, mvm->sta_drained);
schedule_work(&mvm->sta_drained_wk);
}
if (txq_id >= mvm->first_agg_queue)
goto out;
/* We can't free more than one frame at once on a shared queue */
WARN_ON(skb_freed > 1);
/* If we have still frames from this STA nothing to do here */
if (!atomic_sub_and_test(skb_freed, &mvm->pending_frames[sta_id]))
goto out;
if (mvmsta && mvmsta->vif->type == NL80211_IFTYPE_AP) {
/*
* If there are no pending frames for this STA, notify
* mac80211 that this station can go to sleep in its
* STA table.
* If mvmsta is not NULL, sta is valid.
*/
ieee80211_sta_block_awake(mvm->hw, sta, false);
}
if (PTR_ERR(sta) == -EBUSY || PTR_ERR(sta) == -ENOENT) {
/*
* We are draining and this was the last packet - pre_rcu_remove
* has been called already. We might be after the
* synchronize_net already.
* Don't rely on iwl_mvm_rm_sta to see the empty Tx queues.
*/
set_bit(sta_id, mvm->sta_drained);
schedule_work(&mvm->sta_drained_wk);
}
out:
rcu_read_unlock();
}