Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 276 insertions, 0 deletions

diff --git a/net/core/dst.c b/net/core/dst.c
new file mode 100644
index 000000000000..3bf6cc434814
--- /dev/null
+++ b/net/core/dst.c
@@ -0,0 +1,276 @@
+/*
+ * 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/sched.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 struct timer_list dst_gc_timer =
+        TIMER_INITIALIZER(dst_run_gc, DST_GC_MIN, 0);
+
+static void dst_run_gc(unsigned long dummy)
+{
+        int    delayed = 0;
+        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;
+        while ((dst = *dstp) != NULL) {
+                if (atomic_read(&dst->__refcnt)) {
+                        dstp = &dst->next;
+                        delayed++;
+                        continue;
+                }
+                *dstp = dst->next;
+
+                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 ((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);
+
+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_alloc(ops->kmem_cachep, SLAB_ATOMIC);
+        if (!dst)
+                return NULL;
+        memset(dst, 0, ops->entry_size);
+        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) {
+                if (atomic_dec_and_test(&dst->__refcnt)) {
+                        /* We were real parent of this dst, so kill child. */
+                        if (dst->flags&DST_NOHASH)
+                                goto again;
+                } else {
+                        /* Child is still referenced, return it for freeing. */
+                        if (dst->flags&DST_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);