Commit cf66f9d4 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk Committed by David S. Miller
Browse files

xen/netfront: add netconsole support. 



add polling interface to xen-netfront device to support netconsole

This patch also alters the spin_lock usage to use irqsave variant.
Documentation/networking/netdevices.txt states that start_xmit
can be called with interrupts disabled by netconsole and therefore using
the irqsave/restore locking in this function is looks correct.

Signed-off-by: default avatarTina.Yang <tina.yang@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: default avatarZhenzhong.Duan <zhenzhong.duan@oracle.com>
Tested-by: default avatargurudas.pai <gurudas.pai@oracle.com>
[v1: Copy-n-pasted Ian Campbell comments]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: default avatarIan Campbell <ian.campbell@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c54a4570

drivers/net/xen-netfront.c

+34 −23
Original line number Diff line number Diff line
@@ -489,6 +489,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	int frags = skb_shinfo(skb)->nr_frags;

	unsigned int offset = offset_in_page(data);

	unsigned int len = skb_headlen(skb);

	unsigned long flags;



	frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);

	if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
@@ -498,12 +499,12 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		goto drop;

	}



	spin_lock_irq(&np->tx_lock);

	spin_lock_irqsave(&np->tx_lock, flags);



	if (unlikely(!netif_carrier_ok(dev) ||

		     (frags > 1 && !xennet_can_sg(dev)) ||

		     netif_needs_gso(skb, netif_skb_features(skb)))) {

		spin_unlock_irq(&np->tx_lock);

		spin_unlock_irqrestore(&np->tx_lock, flags);

		goto drop;

	}
@@ -574,7 +575,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (!netfront_tx_slot_available(np))

		netif_stop_queue(dev);



	spin_unlock_irq(&np->tx_lock);

	spin_unlock_irqrestore(&np->tx_lock, flags);



	return NETDEV_TX_OK;
@@ -1228,6 +1229,33 @@ static int xennet_set_features(struct net_device *dev, 
	return 0;

}



static irqreturn_t xennet_interrupt(int irq, void *dev_id)

{

	struct net_device *dev = dev_id;

	struct netfront_info *np = netdev_priv(dev);

	unsigned long flags;



	spin_lock_irqsave(&np->tx_lock, flags);



	if (likely(netif_carrier_ok(dev))) {

		xennet_tx_buf_gc(dev);

		/* Under tx_lock: protects access to rx shared-ring indexes. */

		if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))

			napi_schedule(&np->napi);

	}



	spin_unlock_irqrestore(&np->tx_lock, flags);



	return IRQ_HANDLED;

}



#ifdef CONFIG_NET_POLL_CONTROLLER

static void xennet_poll_controller(struct net_device *dev)

{

	xennet_interrupt(0, dev);

}

#endif



static const struct net_device_ops xennet_netdev_ops = {

	.ndo_open            = xennet_open,

	.ndo_uninit          = xennet_uninit,
@@ -1239,6 +1267,9 @@ static const struct net_device_ops xennet_netdev_ops = { 
	.ndo_validate_addr   = eth_validate_addr,

	.ndo_fix_features    = xennet_fix_features,

	.ndo_set_features    = xennet_set_features,

#ifdef CONFIG_NET_POLL_CONTROLLER

	.ndo_poll_controller = xennet_poll_controller,

#endif

};



static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
@@ -1448,26 +1479,6 @@ static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 
	return 0;

}



static irqreturn_t xennet_interrupt(int irq, void *dev_id)

{

	struct net_device *dev = dev_id;

	struct netfront_info *np = netdev_priv(dev);

	unsigned long flags;



	spin_lock_irqsave(&np->tx_lock, flags);



	if (likely(netif_carrier_ok(dev))) {

		xennet_tx_buf_gc(dev);

		/* Under tx_lock: protects access to rx shared-ring indexes. */

		if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))

			napi_schedule(&np->napi);

	}



	spin_unlock_irqrestore(&np->tx_lock, flags);



	return IRQ_HANDLED;

}



static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)

{

	struct xen_netif_tx_sring *txs;

CRA Git | Maintained and supported by SUSTech CRA and CCSE