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>
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index fa67905..db638b4 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -489,6 +489,7 @@
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 @@
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 @@
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 @@
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 @@
.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 @@
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;