From 2957ed7b65e61b26e75a5c0b02d055ad3dde753e Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 8 May 2007 18:34:17 -0700
Subject: [PATCH] --- yaml --- r: 55951 b: refs/heads/master c:
 572a103ded0ad880f75ce83e99f0512fbb80b5b0 h: refs/heads/master i:   55949:
 a87dc6fb3c609a559606fdce263e3e43deb32cba   55947:
 11e4d7a8a0b7585c0f10d7c135827181d1fbb471   55943:
 63010f499448d733893d6ecbd08dd0e0f22f1888   55935:
 a0b3bc37627f648ae1c16934e6adf67148acbf76 v: v3

---
 [refs]                          |  2 +-
 trunk/include/linux/netdevice.h |  2 ++
 trunk/net/core/link_watch.c     | 50 ++++++++++-----------------------
 3 files changed, 18 insertions(+), 36 deletions(-)

diff --git a/[refs] b/[refs]
index 4a08d2e88a6b..c39a9a3c6167 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c33be3c362f1bc98f6e2d731a274ef138ae80741
+refs/heads/master: 572a103ded0ad880f75ce83e99f0512fbb80b5b0
diff --git a/trunk/include/linux/netdevice.h b/trunk/include/linux/netdevice.h
index 30446222b396..f671cd2f133f 100644
--- a/trunk/include/linux/netdevice.h
+++ b/trunk/include/linux/netdevice.h
@@ -467,6 +467,8 @@ struct net_device
 	/* device index hash chain */
 	struct hlist_node	index_hlist;
 
+	struct net_device	*link_watch_next;
+
 	/* register/unregister state machine */
 	enum { NETREG_UNINITIALIZED=0,
 	       NETREG_REGISTERED,	/* completed register_netdevice */
diff --git a/trunk/net/core/link_watch.c b/trunk/net/core/link_watch.c
index e3c26a9ccad6..71a35da275d4 100644
--- a/trunk/net/core/link_watch.c
+++ b/trunk/net/core/link_watch.c
@@ -19,7 +19,6 @@
 #include <linux/rtnetlink.h>
 #include <linux/jiffies.h>
 #include <linux/spinlock.h>
-#include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
@@ -28,7 +27,6 @@
 
 enum lw_bits {
 	LW_RUNNING = 0,
-	LW_SE_USED
 };
 
 static unsigned long linkwatch_flags;
@@ -37,17 +35,9 @@ static unsigned long linkwatch_nextevent;
 static void linkwatch_event(struct work_struct *dummy);
 static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
 
-static LIST_HEAD(lweventlist);
+static struct net_device *lweventlist;
 static DEFINE_SPINLOCK(lweventlist_lock);
 
-struct lw_event {
-	struct list_head list;
-	struct net_device *dev;
-};
-
-/* Avoid kmalloc() for most systems */
-static struct lw_event singleevent;
-
 static unsigned char default_operstate(const struct net_device *dev)
 {
 	if (!netif_carrier_ok(dev))
@@ -90,21 +80,23 @@ static void rfc2863_policy(struct net_device *dev)
 /* Must be called with the rtnl semaphore held */
 void linkwatch_run_queue(void)
 {
-	struct list_head head, *n, *next;
+	struct net_device *next;
 
 	spin_lock_irq(&lweventlist_lock);
-	list_replace_init(&lweventlist, &head);
+	next = lweventlist;
+	lweventlist = NULL;
 	spin_unlock_irq(&lweventlist_lock);
 
-	list_for_each_safe(n, next, &head) {
-		struct lw_event *event = list_entry(n, struct lw_event, list);
-		struct net_device *dev = event->dev;
+	while (next) {
+		struct net_device *dev = next;
 
-		if (event == &singleevent) {
-			clear_bit(LW_SE_USED, &linkwatch_flags);
-		} else {
-			kfree(event);
-		}
+		next = dev->link_watch_next;
+
+		/*
+		 * Make sure the above read is complete since it can be
+		 * rewritten as soon as we clear the bit below.
+		 */
+		smp_mb__before_clear_bit();
 
 		/* We are about to handle this device,
 		 * so new events can be accepted
@@ -147,24 +139,12 @@ void linkwatch_fire_event(struct net_device *dev)
 {
 	if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
 		unsigned long flags;
-		struct lw_event *event;
-
-		if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) {
-			event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC);
-
-			if (unlikely(event == NULL)) {
-				clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
-				return;
-			}
-		} else {
-			event = &singleevent;
-		}
 
 		dev_hold(dev);
-		event->dev = dev;
 
 		spin_lock_irqsave(&lweventlist_lock, flags);
-		list_add_tail(&event->list, &lweventlist);
+		dev->link_watch_next = lweventlist;
+		lweventlist = dev;
 		spin_unlock_irqrestore(&lweventlist_lock, flags);
 
 		if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) {