From 711531939f77c1a014ab75671b1aa03288c73d65 Mon Sep 17 00:00:00 2001
From: t_jeang <devnull@localhost>
Date: Tue, 6 Jan 2009 12:06:02 +0000
Subject: [PATCH] imported patch netback-thread

---
 drivers/xen/netback/netback.c | 69 ++++++++++++++++++++++++++++-------
 1 file changed, 55 insertions(+), 14 deletions(-)

diff --git a/drivers/xen/netback/netback.c b/drivers/xen/netback/netback.c
index c91849d9..11518632 100644
--- a/drivers/xen/netback/netback.c
+++ b/drivers/xen/netback/netback.c
@@ -37,6 +37,7 @@
 #include "common.h"
 #include <xen/balloon.h>
 #include <xen/interface/memory.h>
+#include <linux/kthread.h>
 
 /*define NETBE_DEBUG_INTERRUPT*/
 
@@ -65,11 +66,9 @@ static netif_rx_response_t *make_rx_response(netif_t *netif,
 					     u16      size,
 					     u16      flags);
 
-static void net_tx_action(unsigned long unused);
-static DECLARE_TASKLET(net_tx_tasklet, net_tx_action, 0);
-
-static void net_rx_action(unsigned long unused);
-static DECLARE_TASKLET(net_rx_tasklet, net_rx_action, 0);
+static void net_rx_action(void);
+static void net_tx_action(void);
+static DECLARE_WAIT_QUEUE_HEAD(netbk_action_wq);
 
 static struct timer_list net_timer;
 static struct timer_list netbk_tx_pending_timer;
@@ -194,7 +193,7 @@ static inline void maybe_schedule_tx_action(void)
 	smp_mb();
 	if ((NR_PENDING_REQS < (MAX_PENDING_REQS/2)) &&
 	    !list_empty(&net_schedule_list))
-		tasklet_schedule(&net_tx_tasklet);
+		wake_up(&netbk_action_wq);
 }
 
 static struct sk_buff *netbk_copy_skb(struct sk_buff *skb)
@@ -378,7 +377,7 @@ int netif_be_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	}
 
 	skb_queue_tail(&rx_queue, skb);
-	tasklet_schedule(&net_rx_tasklet);
+	wake_up(&netbk_action_wq);
 
 	return 0;
 
@@ -676,7 +675,12 @@ struct skb_cb_overlay {
 	int meta_slots_used;
 };
 
-static void net_rx_action(unsigned long unused)
+static inline int net_rx_action_work_to_do(void)
+{
+	return !skb_queue_empty(&rx_queue);
+}
+
+static void net_rx_action(void)
 {
 	netif_t *netif = NULL;
 	s8 status;
@@ -880,9 +884,11 @@ static void net_rx_action(unsigned long unused)
 		notify_remote_via_irq(irq);
 	}
 
+#if 0
 	/* More work to do? */
 	if (!skb_queue_empty(&rx_queue) && !timer_pending(&net_timer))
-		tasklet_schedule(&net_rx_tasklet);
+		wake_up(&netbk_action_wq);
+#endif
 #if 0
 	else
 		xen_network_done_notify();
@@ -891,12 +897,12 @@ static void net_rx_action(unsigned long unused)
 
 static void net_alarm(unsigned long unused)
 {
-	tasklet_schedule(&net_rx_tasklet);
+	wake_up(&netbk_action_wq);
 }
 
 static void netbk_tx_pending_timeout(unsigned long unused)
 {
-	tasklet_schedule(&net_tx_tasklet);
+	wake_up(&netbk_action_wq);
 }
 
 struct net_device_stats *netif_be_get_stats(struct net_device *dev)
@@ -1326,8 +1332,20 @@ static int netbk_set_skb_gso(struct sk_buff *skb, struct netif_extra_info *gso)
 	return 0;
 }
 
+static inline int net_tx_action_work_to_do(void)
+{
+	if (dealloc_cons != dealloc_prod)
+		return 1;
+
+	if (((NR_PENDING_REQS + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
+		!list_empty(&net_schedule_list))
+		return 1;
+
+	return 0;
+}
+
 /* Called after netfront has transmitted */
-static void net_tx_action(unsigned long unused)
+static void net_tx_action(void)
 {
 	struct list_head *ent;
 	struct sk_buff *skb;
@@ -1559,7 +1577,7 @@ static void net_tx_action(unsigned long unused)
 			continue;
 		}
 
-		netif_rx(skb);
+		netif_rx_ni(skb);
 		netif->dev->last_rx = jiffies;
 	}
 
@@ -1585,7 +1603,7 @@ static void netif_idx_release(u16 pending_idx)
 	dealloc_prod++;
 	spin_unlock_irqrestore(&_lock, flags);
 
-	tasklet_schedule(&net_tx_tasklet);
+	wake_up(&netbk_action_wq);
 }
 
 static void netif_page_release(struct page *page)
@@ -1661,6 +1679,24 @@ static netif_rx_response_t *make_rx_response(netif_t *netif,
 	return resp;
 }
 
+static int netbk_action_thread(void *unused)
+{
+	while (1) {
+		wait_event_interruptible(netbk_action_wq,
+			net_rx_action_work_to_do() || net_tx_action_work_to_do());
+		cond_resched();
+
+		if (net_rx_action_work_to_do())
+			net_rx_action();
+
+		if (net_tx_action_work_to_do())
+			net_tx_action();
+	}
+
+	return 0;
+}
+
+
 #ifdef NETBE_DEBUG_INTERRUPT
 static irqreturn_t netif_be_dbg(int irq, void *dev_id, struct pt_regs *regs)
 {
@@ -1699,6 +1735,7 @@ static int __init netback_init(void)
 {
 	int i;
 	struct page *page;
+	struct task_struct *task;
 
 	if (!is_running_on_xen())
 		return -ENODEV;
@@ -1752,6 +1789,10 @@ static int __init netback_init(void)
 
 	netif_xenbus_init();
 
+	task = kthread_run(netbk_action_thread, NULL, "netback");
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+
 #ifdef NETBE_DEBUG_INTERRUPT
 	(void)bind_virq_to_irqhandler(VIRQ_DEBUG,
 				      0,
-- 
2.39.5