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

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID c9c40f6baba00f8fbc3fe6bb3338fb975e31849c
# Parent  e0bbba2b9850f258197ea5df59d6e7c53cbb0398
[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@xxxxxxxxxxxxxxxxxxx>
---
 linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c |   32 +++++--------------
 1 files changed, 9 insertions(+), 23 deletions(-)

diff -r e0bbba2b9850 -r c9c40f6baba0 
linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
--- a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c      Thu May 25 
14:15:49 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c      Thu May 25 
14:29:21 2006 +0100
@@ -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
@@ -143,14 +137,6 @@ static inline unsigned short get_id_from
        list[0] = list[id];
        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)
@@ -342,7 +328,6 @@ static int setup_device(struct xenbus_de
        }
        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
        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(str
        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_
 
        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 
 
        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_d
         * 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_
        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,
@@ -1241,9 +1226,10 @@ static struct net_device * __devinit cre
        }
 
        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(str
        /* 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);
 

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