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ar9170: fix hang on stop

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This patch fixes a locking problem which freezes the network core.

The deadlock goes as follows:
- ar9170_op_stop - is called
1. change the state to IDLE
2. > take the MUTEX <
3. cancel_SYNC all pending work, which means
    "block until a work_struct's callback has terminated"
=>  if filter_config_work was queued it tries to get the MUTEX,
       before checking the device state...

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Christian Lamparter
2009-03-28 01:46:14 +01:00
committed by John W. Linville
parent 807e37394b
commit 32c1628f15
1 changed files with 4 additions and 3 deletions
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7
drivers/net/wireless/ar9170/main.c
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@ -742,8 +742,9 @@ static void ar9170_op_stop(struct ieee80211_hw *hw)
if (IS_STARTED(ar)) if (IS_STARTED(ar))
ar->state = AR9170_IDLE; ar->state = AR9170_IDLE;
mutex_lock(&ar->mutex); flush_workqueue(ar->hw->workqueue);
mutex_lock(&ar->mutex);
cancel_delayed_work_sync(&ar->tx_status_janitor); cancel_delayed_work_sync(&ar->tx_status_janitor);
cancel_work_sync(&ar->filter_config_work); cancel_work_sync(&ar->filter_config_work);
cancel_work_sync(&ar->beacon_work); cancel_work_sync(&ar->beacon_work);
@ -1123,10 +1124,10 @@ static void ar9170_set_filters(struct work_struct *work)
filter_config_work); filter_config_work);
int err; int err;
mutex_lock(&ar->mutex);
if (unlikely(!IS_STARTED(ar))) if (unlikely(!IS_STARTED(ar)))
goto unlock; return ;
mutex_lock(&ar->mutex);
if (ar->filter_changed & AR9170_FILTER_CHANGED_PROMISC) { if (ar->filter_changed & AR9170_FILTER_CHANGED_PROMISC) {
err = ar9170_set_operating_mode(ar); err = ar9170_set_operating_mode(ar);
if (err) if (err)