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: Tina.Yang <tina.yang@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Zhenzhong.Duan <zhenzhong.duan@oracle.com> Tested-by: gurudas.pai <gurudas.pai@oracle.com> [v1: Copy-n-pasted Ian Campbell comments] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -489,6 +489,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
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int frags = skb_shinfo(skb)->nr_frags;
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unsigned int offset = offset_in_page(data);
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unsigned int len = skb_headlen(skb);
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unsigned long flags;
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frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);
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if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
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@ -498,12 +499,12 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
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goto drop;
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}
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spin_lock_irq(&np->tx_lock);
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spin_lock_irqsave(&np->tx_lock, flags);
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if (unlikely(!netif_carrier_ok(dev) ||
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(frags > 1 && !xennet_can_sg(dev)) ||
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netif_needs_gso(skb, netif_skb_features(skb)))) {
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spin_unlock_irq(&np->tx_lock);
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spin_unlock_irqrestore(&np->tx_lock, flags);
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goto drop;
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}
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@ -574,7 +575,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
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if (!netfront_tx_slot_available(np))
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netif_stop_queue(dev);
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spin_unlock_irq(&np->tx_lock);
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spin_unlock_irqrestore(&np->tx_lock, flags);
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return NETDEV_TX_OK;
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@ -1228,6 +1229,33 @@ static int xennet_set_features(struct net_device *dev,
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return 0;
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}
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static irqreturn_t xennet_interrupt(int irq, void *dev_id)
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{
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struct net_device *dev = dev_id;
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struct netfront_info *np = netdev_priv(dev);
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unsigned long flags;
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spin_lock_irqsave(&np->tx_lock, flags);
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if (likely(netif_carrier_ok(dev))) {
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xennet_tx_buf_gc(dev);
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/* Under tx_lock: protects access to rx shared-ring indexes. */
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if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
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napi_schedule(&np->napi);
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}
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spin_unlock_irqrestore(&np->tx_lock, flags);
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return IRQ_HANDLED;
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}
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#ifdef CONFIG_NET_POLL_CONTROLLER
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static void xennet_poll_controller(struct net_device *dev)
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{
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xennet_interrupt(0, dev);
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}
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#endif
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static const struct net_device_ops xennet_netdev_ops = {
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.ndo_open = xennet_open,
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.ndo_uninit = xennet_uninit,
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@ -1239,6 +1267,9 @@ static const struct net_device_ops xennet_netdev_ops = {
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.ndo_validate_addr = eth_validate_addr,
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.ndo_fix_features = xennet_fix_features,
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.ndo_set_features = xennet_set_features,
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#ifdef CONFIG_NET_POLL_CONTROLLER
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.ndo_poll_controller = xennet_poll_controller,
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#endif
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};
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static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
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@ -1448,26 +1479,6 @@ static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
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return 0;
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}
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static irqreturn_t xennet_interrupt(int irq, void *dev_id)
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{
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struct net_device *dev = dev_id;
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struct netfront_info *np = netdev_priv(dev);
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unsigned long flags;
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spin_lock_irqsave(&np->tx_lock, flags);
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if (likely(netif_carrier_ok(dev))) {
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xennet_tx_buf_gc(dev);
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/* Under tx_lock: protects access to rx shared-ring indexes. */
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if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
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napi_schedule(&np->napi);
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}
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spin_unlock_irqrestore(&np->tx_lock, flags);
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return IRQ_HANDLED;
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}
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static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
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{
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struct xen_netif_tx_sring *txs;
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