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Subject[10/53] rt2x00: Fix sleep-while-atomic bug in powersaving code.
3.1-stable review patch.  If anyone has any objections, please let me know.

------------------
From: Gertjan van Wingerde <gwingerde@gmail.com>

commit ed66ba472a742cd8df37d7072804b2111cdb1014 upstream.

The generic powersaving code that determines after reception of a frame
whether the device should go back to sleep or whether is could stay
awake was calling rt2x00lib_config directly from RX tasklet context.
On a number of the devices this call can actually sleep, due to having
to confirm that the sleeping commands have been executed successfully.

Fix this by moving the call to rt2x00lib_config to a workqueue call.

This fixes bug https://bugzilla.redhat.com/show_bug.cgi?id=731672

Tested-by: Tomas Trnka <tomastrnka@gmx.com>
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/net/wireless/rt2x00/rt2x00.h | 1 +
drivers/net/wireless/rt2x00/rt2x00dev.c | 22 ++++++++++++++++++++--
2 files changed, 21 insertions(+), 2 deletions(-)
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -923,6 +923,7 @@ struct rt2x00_dev {
* Powersaving work
*/
struct delayed_work autowakeup_work;
+ struct work_struct sleep_work;

/*
* Data queue arrays for RX, TX, Beacon and ATIM.
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -449,6 +449,23 @@ static u8 *rt2x00lib_find_ie(u8 *data, u
return NULL;
}

+static void rt2x00lib_sleep(struct work_struct *work)
+{
+ struct rt2x00_dev *rt2x00dev =
+ container_of(work, struct rt2x00_dev, sleep_work);
+
+ if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
+ return;
+
+ /*
+ * Check again is powersaving is enabled, to prevent races from delayed
+ * work execution.
+ */
+ if (!test_bit(CONFIG_POWERSAVING, &rt2x00dev->flags))
+ rt2x00lib_config(rt2x00dev, &rt2x00dev->hw->conf,
+ IEEE80211_CONF_CHANGE_PS);
+}
+
static void rt2x00lib_rxdone_check_ps(struct rt2x00_dev *rt2x00dev,
struct sk_buff *skb,
struct rxdone_entry_desc *rxdesc)
@@ -496,8 +513,7 @@ static void rt2x00lib_rxdone_check_ps(st
cam |= (tim_ie->bitmap_ctrl & 0x01);

if (!cam && !test_bit(CONFIG_POWERSAVING, &rt2x00dev->flags))
- rt2x00lib_config(rt2x00dev, &rt2x00dev->hw->conf,
- IEEE80211_CONF_CHANGE_PS);
+ queue_work(rt2x00dev->workqueue, &rt2x00dev->sleep_work);
}

static int rt2x00lib_rxdone_read_signal(struct rt2x00_dev *rt2x00dev,
@@ -1121,6 +1137,7 @@ int rt2x00lib_probe_dev(struct rt2x00_de

INIT_WORK(&rt2x00dev->intf_work, rt2x00lib_intf_scheduled);
INIT_DELAYED_WORK(&rt2x00dev->autowakeup_work, rt2x00lib_autowakeup);
+ INIT_WORK(&rt2x00dev->sleep_work, rt2x00lib_sleep);

/*
* Let the driver probe the device to detect the capabilities.
@@ -1177,6 +1194,7 @@ void rt2x00lib_remove_dev(struct rt2x00_
*/
cancel_work_sync(&rt2x00dev->intf_work);
cancel_delayed_work_sync(&rt2x00dev->autowakeup_work);
+ cancel_work_sync(&rt2x00dev->sleep_work);
if (rt2x00_is_usb(rt2x00dev)) {
del_timer_sync(&rt2x00dev->txstatus_timer);
cancel_work_sync(&rt2x00dev->rxdone_work);



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