[v2.6.34-stable 28/77] p54spi: Fix workqueue deadlock

Paul Gortmaker
2013-01-08T23:48:51Z

From: Michael Büsch <m@bues.ch>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------

commit 2d1618170eb493d18f66f2ac03775409a6fb97c6 upstream.

priv->work must not be synced while priv->mutex is locked, because
the mutex is taken in the work handler.
Move cancel_work_sync down to after the device shutdown code.
This is safe, because the work handler checks fw_state and bails out
early in case of a race.

Signed-off-by: Michael Buesch <m@bues.ch>
Acked-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/net/wireless/p54/p54spi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/p54/p54spi.c b/drivers/net/wireless/p54/p54spi.c
index 4cede24..8cf0301 100644
--- a/drivers/net/wireless/p54/p54spi.c
+++ b/drivers/net/wireless/p54/p54spi.c
@@ -582,8 +582,6 @@ static void p54spi_op_stop(struct ieee80211_hw *dev)

WARN_ON(priv->fw_state != FW_STATE_READY);

- cancel_work_sync(&priv->work);
-
p54spi_power_off(priv);
spin_lock_irqsave(&priv->tx_lock, flags);
INIT_LIST_HEAD(&priv->tx_pending);
@@ -591,6 +589,8 @@ static void p54spi_op_stop(struct ieee80211_hw *dev)

priv->fw_state = FW_STATE_OFF;
mutex_unlock(&priv->mutex);
+
+ cancel_work_sync(&priv->work);
}

static int __devinit p54spi_probe(struct spi_device *spi)
--
1.7.12.1