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-rw-r--r--include/linux/netdevice.h2
-rw-r--r--net/core/link_watch.c50
2 files changed, 17 insertions, 35 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 30446222b39..f671cd2f133 100644
--- a/include/linux/netdevice.h
+++ b/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/net/core/link_watch.c b/net/core/link_watch.c
index e3c26a9ccad..71a35da275d 100644
--- 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)) {