Commit b7a861a6 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: iss: clean up per-device locking in network driver 



Per-device locking in the ISS network driver is used to protect poll
timer and stats updates. Stat collection is not protected.
Remove per-device locking everywhere except the stats updates. Replace
ndo_get_stats callback with ndo_get_stats64 and use proper locking there
as well.
As a side effect this fixes possible deadlock between iss_net_close
and iss_net_timer.

Reported by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent fd165016

arch/xtensa/platforms/iss/network.c

+18 −21
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ struct iss_net_private { 
	struct net_device *dev;

	struct platform_device pdev;

	struct timer_list tl;

	struct net_device_stats stats;

	struct rtnl_link_stats64 stats;



	struct timer_list timer;

	unsigned int timer_val;
@@ -281,7 +281,9 @@ static int iss_net_rx(struct net_device *dev) 


	skb = dev_alloc_skb(dev->mtu + 2 + ETH_HEADER_OTHER);

	if (skb == NULL) {

		spin_lock_bh(&lp->lock);

		lp->stats.rx_dropped++;

		spin_unlock_bh(&lp->lock);

		return 0;

	}
@@ -298,8 +300,10 @@ static int iss_net_rx(struct net_device *dev) 
		skb_trim(skb, pkt_len);

		skb->protocol = lp->tp.protocol(skb);



		spin_lock_bh(&lp->lock);

		lp->stats.rx_bytes += skb->len;

		lp->stats.rx_packets++;

		spin_unlock_bh(&lp->lock);

		netif_rx(skb);

		return pkt_len;

	}
@@ -314,13 +318,9 @@ static int iss_net_poll(struct iss_net_private *lp) 
	if (!netif_running(lp->dev))

		return 0;



	spin_lock(&lp->lock);



	while ((err = iss_net_rx(lp->dev)) > 0)

		ret++;



	spin_unlock(&lp->lock);



	if (err < 0) {

		pr_err("Device '%s' read returned %d, shutting it down\n",

		       lp->dev->name, err);
@@ -338,9 +338,7 @@ static void iss_net_timer(struct timer_list *t) 
	struct iss_net_private *lp = from_timer(lp, t, timer);



	iss_net_poll(lp);

	spin_lock(&lp->lock);

	mod_timer(&lp->timer, jiffies + lp->timer_val);

	spin_unlock(&lp->lock);

}
@@ -349,11 +347,9 @@ static int iss_net_open(struct net_device *dev) 
	struct iss_net_private *lp = netdev_priv(dev);

	int err;



	spin_lock_bh(&lp->lock);



	err = lp->tp.open(lp);

	if (err < 0)

		goto out;

		return err;



	netif_start_queue(dev);
@@ -368,22 +364,17 @@ static int iss_net_open(struct net_device *dev) 
	lp->timer_val = ISS_NET_TIMER_VALUE;

	mod_timer(&lp->timer, jiffies + lp->timer_val);



out:

	spin_unlock_bh(&lp->lock);

	return err;

}



static int iss_net_close(struct net_device *dev)

{

	struct iss_net_private *lp = netdev_priv(dev);

	netif_stop_queue(dev);

	spin_lock_bh(&lp->lock);



	netif_stop_queue(dev);

	del_timer_sync(&lp->timer);



	lp->tp.close(lp);



	spin_unlock_bh(&lp->lock);

	return 0;

}
@@ -393,13 +384,14 @@ static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	int len;



	netif_stop_queue(dev);

	spin_lock_bh(&lp->lock);



	len = lp->tp.write(lp, &skb);



	if (len == skb->len) {

		spin_lock_bh(&lp->lock);

		lp->stats.tx_packets++;

		lp->stats.tx_bytes += skb->len;

		spin_unlock_bh(&lp->lock);

		netif_trans_update(dev);

		netif_start_queue(dev);
@@ -408,24 +400,29 @@ static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev) 


	} else if (len == 0) {

		netif_start_queue(dev);

		spin_lock_bh(&lp->lock);

		lp->stats.tx_dropped++;

		spin_unlock_bh(&lp->lock);



	} else {

		netif_start_queue(dev);

		pr_err("%s: %s failed(%d)\n", dev->name, __func__, len);

	}



	spin_unlock_bh(&lp->lock);



	dev_kfree_skb(skb);

	return NETDEV_TX_OK;

}





static struct net_device_stats *iss_net_get_stats(struct net_device *dev)

static void iss_net_get_stats64(struct net_device *dev,

				struct rtnl_link_stats64 *stats)

{

	struct iss_net_private *lp = netdev_priv(dev);

	return &lp->stats;



	spin_lock_bh(&lp->lock);

	*stats = lp->stats;

	spin_unlock_bh(&lp->lock);

}



static void iss_net_set_multicast_list(struct net_device *dev)
@@ -457,7 +454,7 @@ static int driver_registered; 
static const struct net_device_ops iss_netdev_ops = {

	.ndo_open		= iss_net_open,

	.ndo_stop		= iss_net_close,

	.ndo_get_stats		= iss_net_get_stats,

	.ndo_get_stats64	= iss_net_get_stats64,

	.ndo_start_xmit		= iss_net_start_xmit,

	.ndo_validate_addr	= eth_validate_addr,

	.ndo_change_mtu		= iss_net_change_mtu,