From cf66f9d48a9c95baf8f13b199a633ce1c4cf952a Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Mon, 23 Jan 2012 08:24:43 +0000 Subject: [PATCH] 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 Cc: Jeremy Fitzhardinge Signed-off-by: Zhenzhong.Duan Tested-by: gurudas.pai [v1: Copy-n-pasted Ian Campbell comments] Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Ian Campbell Signed-off-by: David S. Miller --- drivers/net/xen-netfront.c | 57 +++++++++++++++++++++++--------------- 1 file changed, 34 insertions(+), 23 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index fa679057630..db638b4454e 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -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; -- 2.41.0