[NET] link_watch: Move link watch list into net_device

[deliverable/linux.git] / net / core / link_watch.c

diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index e3c26a9ccad6e097b098bc0783d9076c589199d9..71a35da275d4fd24c2d696b00031ca5836495b46 100644 (file)
--- a/net/core/link_watch.c
+++ b/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)) {