Revert "net: remove zap_completion_queue"
This reverts commit 15e83ed78864d0625e87a85f09b297c0919a4797.
As explained by Johannes Berg, the optimization made here is
invalid. Or, at best, incomplete.
Not only destructor invocation, but conntract entry releasing
must be executed outside of hw IRQ context.
So just checking "skb->destructor" is insufficient.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c2b7a8b..537e01a 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -49,6 +49,7 @@
(MAX_UDP_CHUNK + sizeof(struct udphdr) + \
sizeof(struct iphdr) + sizeof(struct ethhdr))
+static void zap_completion_queue(void);
static void arp_reply(struct sk_buff *skb);
static unsigned int carrier_timeout = 4;
@@ -196,6 +197,7 @@
service_arp_queue(dev->npinfo);
+ zap_completion_queue();
}
EXPORT_SYMBOL(netpoll_poll_dev);
@@ -221,11 +223,40 @@
spin_unlock_irqrestore(&skb_pool.lock, flags);
}
+static void zap_completion_queue(void)
+{
+ unsigned long flags;
+ struct softnet_data *sd = &get_cpu_var(softnet_data);
+
+ if (sd->completion_queue) {
+ struct sk_buff *clist;
+
+ local_irq_save(flags);
+ clist = sd->completion_queue;
+ sd->completion_queue = NULL;
+ local_irq_restore(flags);
+
+ while (clist != NULL) {
+ struct sk_buff *skb = clist;
+ clist = clist->next;
+ if (skb->destructor) {
+ atomic_inc(&skb->users);
+ dev_kfree_skb_any(skb); /* put this one back */
+ } else {
+ __kfree_skb(skb);
+ }
+ }
+ }
+
+ put_cpu_var(softnet_data);
+}
+
static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
{
int count = 0;
struct sk_buff *skb;
+ zap_completion_queue();
refill_skbs();
repeat: