From: kaf24@firebug.cl.cam.ac.uk <kaf24@firebug.cl.cam.ac.uk>
Date: Thu, 25 May 2006 13:29:21 +0000 (+0100)
Subject: [NET] front: Use netif_carrier to model backend-connection state.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~16025^2~20
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=4cebc4c9b20597d96855f41d39047cbda78335a4;p=xen.git

[NET] front: Use netif_carrier to model backend-connection state.

The tristate backend_state really only needs to be a boolean.  In fact
other virtualisation network drivers such as the s390 already model this
using netif_carrier_*.  So by converting backend_state over to the net
carrier flag we can tap into existing infrastructure rather than creating
new ones.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
index 02f241c0b7..f4f68a2e23 100644
--- a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
+++ b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
@@ -89,12 +89,6 @@ struct netfront_info {
 	unsigned int handle;
 	unsigned int evtchn, irq;
 
-	/* What is the status of our connection to the remote backend? */
-#define BEST_CLOSED       0
-#define BEST_DISCONNECTED 1
-#define BEST_CONNECTED    2
-	unsigned int backend_state;
-
 	/* Receive-ring batched refills. */
 #define RX_MIN_TARGET 8
 #define RX_DFL_MIN_TARGET 64
@@ -144,14 +138,6 @@ static inline unsigned short get_id_from_freelist(struct sk_buff **list)
 	return id;
 }
 
-#ifdef DEBUG
-static const char *be_state_name[] = {
-	[BEST_CLOSED]       = "closed",
-	[BEST_DISCONNECTED] = "disconnected",
-	[BEST_CONNECTED]    = "connected",
-};
-#endif
-
 #define DPRINTK(fmt, args...) pr_debug("netfront (%s:%d) " fmt, \
                                        __FUNCTION__, __LINE__, ##args)
 #define IPRINTK(fmt, args...)				\
@@ -342,7 +328,6 @@ static int setup_device(struct xenbus_device *dev, struct netfront_info *info)
 	}
 	memset(txs, 0, PAGE_SIZE);
 	memset(rxs, 0, PAGE_SIZE);
-	info->backend_state = BEST_DISCONNECTED;
 
 	SHARED_RING_INIT(txs);
 	FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
@@ -465,7 +450,7 @@ static void network_tx_buf_gc(struct net_device *dev)
 	struct netfront_info *np = netdev_priv(dev);
 	struct sk_buff *skb;
 
-	if (np->backend_state != BEST_CONNECTED)
+	if (unlikely(!netif_carrier_ok(dev)))
 		return;
 
 	do {
@@ -527,7 +512,7 @@ static void network_alloc_rx_buffers(struct net_device *dev)
 	struct xen_memory_reservation reservation;
 	grant_ref_t ref;
 
-	if (unlikely(np->backend_state != BEST_CONNECTED))
+	if (unlikely(!netif_carrier_ok(dev)))
 		return;
 
 	/*
@@ -662,7 +647,7 @@ static int network_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	spin_lock_irq(&np->tx_lock);
 
-	if (np->backend_state != BEST_CONNECTED) {
+	if (unlikely(!netif_carrier_ok(dev))) {
 		spin_unlock_irq(&np->tx_lock);
 		goto drop;
 	}
@@ -748,7 +733,7 @@ static int netif_poll(struct net_device *dev, int *pbudget)
 
 	spin_lock(&np->rx_lock);
 
-	if (np->backend_state != BEST_CONNECTED) {
+	if (unlikely(!netif_carrier_ok(dev))) {
 		spin_unlock(&np->rx_lock);
 		return 0;
 	}
@@ -1041,7 +1026,7 @@ static void network_connect(struct net_device *dev)
 	 * domain a kick because we've probably just requeued some
 	 * packets.
 	 */
-	np->backend_state = BEST_CONNECTED;
+	netif_carrier_on(dev);
 	notify_remote_via_irq(np->irq);
 	network_tx_buf_gc(dev);
 
@@ -1055,7 +1040,7 @@ static void show_device(struct netfront_info *np)
 	if (np) {
 		IPRINTK("<vif handle=%u %s(%s) evtchn=%u tx=%p rx=%p>\n",
 			np->handle,
-			be_state_name[np->backend_state],
+			netif_carrier_ok(np->netdev) ? "on" : "off",
 			netif_running(np->netdev) ? "open" : "closed",
 			np->evtchn,
 			np->tx,
@@ -1241,10 +1226,11 @@ static struct net_device * __devinit create_netdev(int handle,
 	}
 
 	np                = netdev_priv(netdev);
-	np->backend_state = BEST_CLOSED;
 	np->handle        = handle;
 	np->xbdev         = dev;
 
+	netif_carrier_off(netdev);
+
 	spin_lock_init(&np->tx_lock);
 	spin_lock_init(&np->rx_lock);
 
@@ -1392,7 +1378,7 @@ static void netif_disconnect_backend(struct netfront_info *info)
 	/* Stop old i/f to prevent errors whilst we rebuild the state. */
 	spin_lock_irq(&info->tx_lock);
 	spin_lock(&info->rx_lock);
-	info->backend_state = BEST_DISCONNECTED;
+	netif_carrier_off(info->netdev);
 	spin_unlock(&info->rx_lock);
 	spin_unlock_irq(&info->tx_lock);