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/*
* net/dst.c Protocol independent destination cache.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <asm/segment.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/dst.h>
struct dst_entry * dst_garbage_list;
atomic_t dst_total = ATOMIC_INIT(0);
static unsigned long dst_gc_timer_expires;
static unsigned long dst_gc_timer_inc = DST_GC_MAX;
static void dst_run_gc(unsigned long);
static struct timer_list dst_gc_timer =
{ NULL, NULL, DST_GC_MIN, 0L, dst_run_gc };
#if RT_CACHE_DEBUG >= 2
atomic_t hh_count;
#endif
static void dst_run_gc(unsigned long dummy)
{
int delayed = 0;
struct dst_entry * dst, **dstp;
del_timer(&dst_gc_timer);
dstp = &dst_garbage_list;
while ((dst = *dstp) != NULL) {
if (atomic_read(&dst->use)) {
dstp = &dst->next;
delayed++;
continue;
}
*dstp = dst->next;
dst_destroy(dst);
}
if (!dst_garbage_list) {
dst_gc_timer_inc = DST_GC_MAX;
return;
}
if ((dst_gc_timer_expires += dst_gc_timer_inc) > DST_GC_MAX)
dst_gc_timer_expires = DST_GC_MAX;
dst_gc_timer_inc += DST_GC_INC;
dst_gc_timer.expires = jiffies + dst_gc_timer_expires;
#if RT_CACHE_DEBUG >= 2
printk("dst_total: %d/%d %ld\n",
atomic_read(&dst_total), delayed, dst_gc_timer_expires);
#endif
add_timer(&dst_gc_timer);
}
static int dst_discard(struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
static int dst_blackhole(struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
void * dst_alloc(int size, struct dst_ops * ops)
{
struct dst_entry * dst;
if (ops->gc && atomic_read(&ops->entries) > ops->gc_thresh) {
if (ops->gc())
return NULL;
}
dst = kmalloc(size, GFP_ATOMIC);
if (!dst)
return NULL;
memset(dst, 0, size);
dst->ops = ops;
atomic_set(&dst->refcnt, 0);
dst->lastuse = jiffies;
dst->input = dst_discard;
dst->output = dst_blackhole;
atomic_inc(&dst_total);
atomic_inc(&ops->entries);
return dst;
}
void __dst_free(struct dst_entry * dst)
{
start_bh_atomic();
dst->obsolete = 2;
dst->next = dst_garbage_list;
dst_garbage_list = dst;
if (dst_gc_timer_inc > DST_GC_INC) {
del_timer(&dst_gc_timer);
dst_gc_timer_inc = DST_GC_INC;
dst_gc_timer_expires = DST_GC_MIN;
dst_gc_timer.expires = jiffies + dst_gc_timer_expires;
add_timer(&dst_gc_timer);
}
end_bh_atomic();
}
void dst_destroy(struct dst_entry * dst)
{
struct neighbour *neigh = dst->neighbour;
struct hh_cache *hh = dst->hh;
dst->hh = NULL;
if (hh && atomic_dec_and_test(&hh->hh_refcnt))
kfree(hh);
if (neigh) {
dst->neighbour = NULL;
neigh_release(neigh);
}
atomic_dec(&dst->ops->entries);
if (dst->ops->destroy)
dst->ops->destroy(dst);
atomic_dec(&dst_total);
kfree(dst);
}
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