linux/net/core/dst.c
Tim Schmielau cd354f1ae7 [PATCH] remove many unneeded #includes of sched.h
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-14 08:09:54 -08:00

289 lines
6.4 KiB
C

/*
* net/core/dst.c Protocol independent destination cache.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/types.h>
#include <net/dst.h>
/* Locking strategy:
* 1) Garbage collection state of dead destination cache
* entries is protected by dst_lock.
* 2) GC is run only from BH context, and is the only remover
* of entries.
* 3) Entries are added to the garbage list from both BH
* and non-BH context, so local BH disabling is needed.
* 4) All operations modify state, so a spinlock is used.
*/
static struct dst_entry *dst_garbage_list;
#if RT_CACHE_DEBUG >= 2
static atomic_t dst_total = ATOMIC_INIT(0);
#endif
static DEFINE_SPINLOCK(dst_lock);
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 void ___dst_free(struct dst_entry * dst);
static DEFINE_TIMER(dst_gc_timer, dst_run_gc, DST_GC_MIN, 0);
static void dst_run_gc(unsigned long dummy)
{
int delayed = 0;
int work_performed;
struct dst_entry * dst, **dstp;
if (!spin_trylock(&dst_lock)) {
mod_timer(&dst_gc_timer, jiffies + HZ/10);
return;
}
del_timer(&dst_gc_timer);
dstp = &dst_garbage_list;
work_performed = 0;
while ((dst = *dstp) != NULL) {
if (atomic_read(&dst->__refcnt)) {
dstp = &dst->next;
delayed++;
continue;
}
*dstp = dst->next;
work_performed = 1;
dst = dst_destroy(dst);
if (dst) {
/* NOHASH and still referenced. Unless it is already
* on gc list, invalidate it and add to gc list.
*
* Note: this is temporary. Actually, NOHASH dst's
* must be obsoleted when parent is obsoleted.
* But we do not have state "obsoleted, but
* referenced by parent", so it is right.
*/
if (dst->obsolete > 1)
continue;
___dst_free(dst);
dst->next = *dstp;
*dstp = dst;
dstp = &dst->next;
}
}
if (!dst_garbage_list) {
dst_gc_timer_inc = DST_GC_MAX;
goto out;
}
if (!work_performed) {
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;
} else {
dst_gc_timer_inc = DST_GC_INC;
dst_gc_timer_expires = DST_GC_MIN;
}
#if RT_CACHE_DEBUG >= 2
printk("dst_total: %d/%d %ld\n",
atomic_read(&dst_total), delayed, dst_gc_timer_expires);
#endif
/* if the next desired timer is more than 4 seconds in the future
* then round the timer to whole seconds
*/
if (dst_gc_timer_expires > 4*HZ)
mod_timer(&dst_gc_timer,
round_jiffies(jiffies + dst_gc_timer_expires));
else
mod_timer(&dst_gc_timer, jiffies + dst_gc_timer_expires);
out:
spin_unlock(&dst_lock);
}
static int dst_discard_in(struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
static int dst_discard_out(struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
void * dst_alloc(struct dst_ops * ops)
{
struct dst_entry * dst;
if (ops->gc && atomic_read(&ops->entries) > ops->gc_thresh) {
if (ops->gc())
return NULL;
}
dst = kmem_cache_zalloc(ops->kmem_cachep, GFP_ATOMIC);
if (!dst)
return NULL;
atomic_set(&dst->__refcnt, 0);
dst->ops = ops;
dst->lastuse = jiffies;
dst->path = dst;
dst->input = dst_discard_in;
dst->output = dst_discard_out;
#if RT_CACHE_DEBUG >= 2
atomic_inc(&dst_total);
#endif
atomic_inc(&ops->entries);
return dst;
}
static void ___dst_free(struct dst_entry * dst)
{
/* The first case (dev==NULL) is required, when
protocol module is unloaded.
*/
if (dst->dev == NULL || !(dst->dev->flags&IFF_UP)) {
dst->input = dst_discard_in;
dst->output = dst_discard_out;
}
dst->obsolete = 2;
}
void __dst_free(struct dst_entry * dst)
{
spin_lock_bh(&dst_lock);
___dst_free(dst);
dst->next = dst_garbage_list;
dst_garbage_list = dst;
if (dst_gc_timer_inc > DST_GC_INC) {
dst_gc_timer_inc = DST_GC_INC;
dst_gc_timer_expires = DST_GC_MIN;
mod_timer(&dst_gc_timer, jiffies + dst_gc_timer_expires);
}
spin_unlock_bh(&dst_lock);
}
struct dst_entry *dst_destroy(struct dst_entry * dst)
{
struct dst_entry *child;
struct neighbour *neigh;
struct hh_cache *hh;
smp_rmb();
again:
neigh = dst->neighbour;
hh = dst->hh;
child = dst->child;
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);
if (dst->dev)
dev_put(dst->dev);
#if RT_CACHE_DEBUG >= 2
atomic_dec(&dst_total);
#endif
kmem_cache_free(dst->ops->kmem_cachep, dst);
dst = child;
if (dst) {
int nohash = dst->flags & DST_NOHASH;
if (atomic_dec_and_test(&dst->__refcnt)) {
/* We were real parent of this dst, so kill child. */
if (nohash)
goto again;
} else {
/* Child is still referenced, return it for freeing. */
if (nohash)
return dst;
/* Child is still in his hash table */
}
}
return NULL;
}
/* Dirty hack. We did it in 2.2 (in __dst_free),
* we have _very_ good reasons not to repeat
* this mistake in 2.3, but we have no choice
* now. _It_ _is_ _explicit_ _deliberate_
* _race_ _condition_.
*
* Commented and originally written by Alexey.
*/
static inline void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
if (dst->ops->ifdown)
dst->ops->ifdown(dst, dev, unregister);
if (dev != dst->dev)
return;
if (!unregister) {
dst->input = dst_discard_in;
dst->output = dst_discard_out;
} else {
dst->dev = &loopback_dev;
dev_hold(&loopback_dev);
dev_put(dev);
if (dst->neighbour && dst->neighbour->dev == dev) {
dst->neighbour->dev = &loopback_dev;
dev_put(dev);
dev_hold(&loopback_dev);
}
}
}
static int dst_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
struct dst_entry *dst;
switch (event) {
case NETDEV_UNREGISTER:
case NETDEV_DOWN:
spin_lock_bh(&dst_lock);
for (dst = dst_garbage_list; dst; dst = dst->next) {
dst_ifdown(dst, dev, event != NETDEV_DOWN);
}
spin_unlock_bh(&dst_lock);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block dst_dev_notifier = {
.notifier_call = dst_dev_event,
};
void __init dst_init(void)
{
register_netdevice_notifier(&dst_dev_notifier);
}
EXPORT_SYMBOL(__dst_free);
EXPORT_SYMBOL(dst_alloc);
EXPORT_SYMBOL(dst_destroy);