From: kfraser@localhost.localdomain <kfraser@localhost.localdomain>
Date: Fri, 28 Jul 2006 16:04:55 +0000 (+0100)
Subject: [NET] back: Replace netif->status with netif_carrier_ok
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~15773
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks:///%22http:/www.example.com/cgi/%22https:/%22bookmarks:/?a=commitdiff_plain;h=648ad07608c62e15343bb8834d86600223fbbec2;p=xen.git

[NET] back: Replace netif->status with netif_carrier_ok

The connection status to the frontend can be represented using
netif_carrier_ok instead of netif->status.  As a result, we delay
the construction of the dev qdisc until the carrier comes on.  This
is a prerequisite for adding a tx queue.

By the same token, netif->active is now simply the conjunction of
netif_running and netif_carrier_ok so it too can be removed.

Because netif_carrier_off/netif_carrier_on and rtnl_lock all entail
memory barriers, there is no need to have extra memory barriers around
them.

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

diff --git a/linux-2.6-xen-sparse/drivers/xen/netback/common.h b/linux-2.6-xen-sparse/drivers/xen/netback/common.h
index c52aaa5f6c..3ba0251dca 100644
--- a/linux-2.6-xen-sparse/drivers/xen/netback/common.h
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/common.h
@@ -86,8 +86,6 @@ typedef struct netif_st {
 	struct timer_list credit_timeout;
 
 	/* Miscellaneous private stuff. */
-	enum { DISCONNECTED, DISCONNECTING, CONNECTED } status;
-	int active;
 	struct list_head list;  /* scheduling list */
 	atomic_t         refcnt;
 	struct net_device *dev;
diff --git a/linux-2.6-xen-sparse/drivers/xen/netback/interface.c b/linux-2.6-xen-sparse/drivers/xen/netback/interface.c
index f52e2601b7..b5decfd3ea 100644
--- a/linux-2.6-xen-sparse/drivers/xen/netback/interface.c
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/interface.c
@@ -36,28 +36,20 @@
 
 static void __netif_up(netif_t *netif)
 {
-	struct net_device *dev = netif->dev;
-	netif_tx_lock_bh(dev);
-	netif->active = 1;
-	netif_tx_unlock_bh(dev);
 	enable_irq(netif->irq);
 	netif_schedule_work(netif);
 }
 
 static void __netif_down(netif_t *netif)
 {
-	struct net_device *dev = netif->dev;
 	disable_irq(netif->irq);
-	netif_tx_lock_bh(dev);
-	netif->active = 0;
-	netif_tx_unlock_bh(dev);
 	netif_deschedule_work(netif);
 }
 
 static int net_open(struct net_device *dev)
 {
 	netif_t *netif = netdev_priv(dev);
-	if (netif->status == CONNECTED)
+	if (netif_carrier_ok(dev))
 		__netif_up(netif);
 	netif_start_queue(dev);
 	return 0;
@@ -67,7 +59,7 @@ static int net_close(struct net_device *dev)
 {
 	netif_t *netif = netdev_priv(dev);
 	netif_stop_queue(dev);
-	if (netif->status == CONNECTED)
+	if (netif_carrier_ok(dev))
 		__netif_down(netif);
 	return 0;
 }
@@ -93,11 +85,12 @@ netif_t *netif_alloc(domid_t domid, unsigned int handle, u8 be_mac[ETH_ALEN])
 		return ERR_PTR(-ENOMEM);
 	}
 
+	netif_carrier_off(dev);
+
 	netif = netdev_priv(dev);
 	memset(netif, 0, sizeof(*netif));
 	netif->domid  = domid;
 	netif->handle = handle;
-	netif->status = DISCONNECTED;
 	atomic_set(&netif->refcnt, 1);
 	init_waitqueue_head(&netif->waiting_to_free);
 	netif->dev = dev;
@@ -256,11 +249,9 @@ int netif_map(netif_t *netif, unsigned long tx_ring_ref,
 	netif->rx_req_cons_peek = 0;
 
 	netif_get(netif);
-	wmb(); /* Other CPUs see new state before interface is started. */
 
 	rtnl_lock();
-	netif->status = CONNECTED;
-	wmb();
+	netif_carrier_on(netif->dev);
 	if (netif_running(netif->dev))
 		__netif_up(netif);
 	rtnl_unlock();
@@ -296,20 +287,13 @@ static void netif_free(netif_t *netif)
 
 void netif_disconnect(netif_t *netif)
 {
-	switch (netif->status) {
-	case CONNECTED:
+	if (netif_carrier_ok(netif->dev)) {
 		rtnl_lock();
-		netif->status = DISCONNECTING;
-		wmb();
+		netif_carrier_off(netif->dev);
 		if (netif_running(netif->dev))
 			__netif_down(netif);
 		rtnl_unlock();
 		netif_put(netif);
-		/* fall through */
-	case DISCONNECTED:
-		netif_free(netif);
-		break;
-	default:
-		BUG();
 	}
+	netif_free(netif);
 }
diff --git a/linux-2.6-xen-sparse/drivers/xen/netback/netback.c b/linux-2.6-xen-sparse/drivers/xen/netback/netback.c
index 6795bcd3af..80d16b7576 100644
--- a/linux-2.6-xen-sparse/drivers/xen/netback/netback.c
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/netback.c
@@ -143,7 +143,7 @@ int netif_be_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	BUG_ON(skb->dev != dev);
 
 	/* Drop the packet if the target domain has no receive buffers. */
-	if (!netif->active || 
+	if (unlikely(!netif_running(dev) || !netif_carrier_ok(dev)) ||
 	    (netif->rx_req_cons_peek == netif->rx.sring->req_prod) ||
 	    ((netif->rx_req_cons_peek - netif->rx.rsp_prod_pvt) ==
 	     NET_RX_RING_SIZE))
@@ -404,7 +404,9 @@ static void add_to_net_schedule_list_tail(netif_t *netif)
 		return;
 
 	spin_lock_irq(&net_schedule_list_lock);
-	if (!__on_net_schedule_list(netif) && netif->active) {
+	if (!__on_net_schedule_list(netif) &&
+	    likely(netif_running(netif->dev) &&
+		   netif_carrier_ok(netif->dev))) {
 		list_add_tail(&netif->list, &net_schedule_list);
 		netif_get(netif);
 	}