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Commit 731c6531 authored by Christian Lamparter's avatar Christian Lamparter Committed by John W. Linville
Browse files

p54spi: fix locking warning in p54spi_op_tx 



This patch fixes the following waring:
> ------------[ cut here ]------------
>WARNING: at kernel/softirq.c:138 local_bh_enable+0x54/0xbc()
>Modules linked in: p54spi
>[<c0034ff8>] (dump_stack+0x0/0x14)
>[<c005b1a4>] (warn_on_slowpath+0x0/0x68)
>[<c00604c8>] (local_bh_enable+0x0/0xbc)
>[<bf000000>] (p54spi_op_tx+0x0/0x4c [p54spi])
>[<c01a4d34>] (p54_sta_unlock+0x0/0x78)

p54spi_op_tx needs to be called from different locking contexts.
Therefore we have to protect the linked list with irqsave spinlocks.

Reported-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: default avatarChristian Lamparter <chunkeey@web.de>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 54082819

drivers/net/wireless/p54/p54spi.c

+13 −12
Original line number Diff line number Diff line
@@ -457,9 +457,10 @@ static int p54spi_wq_tx(struct p54s_priv *priv) 
	struct ieee80211_tx_info *info;

	struct p54_tx_info *minfo;

	struct p54s_tx_info *dinfo;

	unsigned long flags;

	int ret = 0;



	spin_lock_bh(&priv->tx_lock);

	spin_lock_irqsave(&priv->tx_lock, flags);



	while (!list_empty(&priv->tx_pending)) {

		entry = list_entry(priv->tx_pending.next,
@@ -467,7 +468,7 @@ static int p54spi_wq_tx(struct p54s_priv *priv) 


		list_del_init(&entry->tx_list);



		spin_unlock_bh(&priv->tx_lock);

		spin_unlock_irqrestore(&priv->tx_lock, flags);



		dinfo = container_of((void *) entry, struct p54s_tx_info,

				     tx_list);
@@ -479,16 +480,14 @@ static int p54spi_wq_tx(struct p54s_priv *priv) 


		ret = p54spi_tx_frame(priv, skb);



		spin_lock_bh(&priv->tx_lock);



		if (ret < 0) {

			p54_free_skb(priv->hw, skb);

			goto out;

		}

			return ret;

		}



out:

	spin_unlock_bh(&priv->tx_lock);

		spin_lock_irqsave(&priv->tx_lock, flags);

	}

	spin_unlock_irqrestore(&priv->tx_lock, flags);

	return ret;

}
@@ -498,12 +497,13 @@ static void p54spi_op_tx(struct ieee80211_hw *dev, struct sk_buff *skb) 
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

	struct p54_tx_info *mi = (struct p54_tx_info *) info->rate_driver_data;

	struct p54s_tx_info *di = (struct p54s_tx_info *) mi->data;

	unsigned long flags;



	BUILD_BUG_ON(sizeof(*di) > sizeof((mi->data)));



	spin_lock_bh(&priv->tx_lock);

	spin_lock_irqsave(&priv->tx_lock, flags);

	list_add_tail(&di->tx_list, &priv->tx_pending);

	spin_unlock_bh(&priv->tx_lock);

	spin_unlock_irqrestore(&priv->tx_lock, flags);



	queue_work(priv->hw->workqueue, &priv->work);

}
@@ -604,6 +604,7 @@ static int p54spi_op_start(struct ieee80211_hw *dev) 
static void p54spi_op_stop(struct ieee80211_hw *dev)

{

	struct p54s_priv *priv = dev->priv;

	unsigned long flags;



	if (mutex_lock_interruptible(&priv->mutex)) {

		/* FIXME: how to handle this error? */
@@ -615,9 +616,9 @@ static void p54spi_op_stop(struct ieee80211_hw *dev) 
	cancel_work_sync(&priv->work);



	p54spi_power_off(priv);

	spin_lock_bh(&priv->tx_lock);

	spin_lock_irqsave(&priv->tx_lock, flags);

	INIT_LIST_HEAD(&priv->tx_pending);

	spin_unlock_bh(&priv->tx_lock);

	spin_unlock_irqrestore(&priv->tx_lock, flags);



	priv->fw_state = FW_STATE_OFF;

	mutex_unlock(&priv->mutex);