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wl12xx: Fix potential interrupt storm 

The interrupt threaded handler exits immediately if the driver's state
is WL1271_STATE_OFF. As a result, the interrupt status is not read. If
the interrupt is level triggered, it will be fired again.

Fix this by disabling interrupts before setting the state to OFF.

Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>
This commit is contained in:
Ido Yariv 2012-01-11 09:42:41 +02:00 committed by Luciano Coelho
parent a454969ede
commit 46b0cc9ffc
1 changed files with 28 additions and 2 deletions
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30
drivers/net/wireless/wl12xx/main.c
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@ -1397,9 +1397,23 @@ int wl1271_plt_stop(struct wl1271 *wl)
wl1271_notice("power down");
/*
* Interrupts must be disabled before setting the state to OFF.
* Otherwise, the interrupt handler might be called and exit without
* reading the interrupt status.
*/
wl1271_disable_interrupts(wl);
mutex_lock(&wl->mutex);
if (wl->state != WL1271_STATE_PLT) {
mutex_unlock(&wl->mutex);
/*
* This will not necessarily enable interrupts as interrupts
* may have been disabled when op_stop was called. It will,
* however, balance the above call to disable_interrupts().
*/
wl1271_enable_interrupts(wl);
wl1271_error("cannot power down because not in PLT "
"state: %d", wl->state);
ret = -EBUSY;
@ -1411,7 +1425,6 @@ int wl1271_plt_stop(struct wl1271 *wl)
mutex_unlock(&wl->mutex);
wl1271_disable_interrupts(wl);
wl1271_flush_deferred_work(wl);
cancel_work_sync(&wl->netstack_work);
cancel_work_sync(&wl->recovery_work);
@ -1773,11 +1786,25 @@ static void wl1271_op_stop(struct ieee80211_hw *hw)
wl1271_debug(DEBUG_MAC80211, "mac80211 stop");
/*
* Interrupts must be disabled before setting the state to OFF.
* Otherwise, the interrupt handler might be called and exit without
* reading the interrupt status.
*/
wl1271_disable_interrupts(wl);
mutex_lock(&wl->mutex);
if (wl->state == WL1271_STATE_OFF) {
mutex_unlock(&wl->mutex);
/*
* This will not necessarily enable interrupts as interrupts
* may have been disabled when op_stop was called. It will,
* however, balance the above call to disable_interrupts().
*/
wl1271_enable_interrupts(wl);
return;
}
/*
* this must be before the cancel_work calls below, so that the work
* functions don't perform further work.
@ -1789,7 +1816,6 @@ static void wl1271_op_stop(struct ieee80211_hw *hw)
list_del(&wl->list);
mutex_unlock(&wl_list_mutex);
wl1271_disable_interrupts(wl);
wl1271_flush_deferred_work(wl);
cancel_delayed_work_sync(&wl->scan_complete_work);
cancel_work_sync(&wl->netstack_work);