[INET]: Consolidate xxx_frag_intern

This routine checks for the existence of a given entry
in the hash table and inserts the new one if needed.

The ->equal callback is used to compare two frag_queue-s
together, but this one is temporary and will be removed
later. The netfilter code and the ipv6 one use the same
routine to compare frags.

The inet_frag_intern() always returns non-NULL pointer,
so convert the inet_frag_queue into protocol specific
one (with the container_of) without any checks.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 0 deletions

diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 484cf512858f..15054eb3d4b9 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -172,3 +172,40 @@ int inet_frag_evictor(struct inet_frags *f)
         return evicted;
 }
 EXPORT_SYMBOL(inet_frag_evictor);
+
+struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
+                struct inet_frags *f, unsigned int hash)
+{
+        struct inet_frag_queue *qp;
+#ifdef CONFIG_SMP
+        struct hlist_node *n;
+#endif
+
+        write_lock(&f->lock);
+#ifdef CONFIG_SMP
+        /* With SMP race we have to recheck hash table, because
+         * such entry could be created on other cpu, while we
+         * promoted read lock to write lock.
+         */
+        hlist_for_each_entry(qp, n, &f->hash[hash], list) {
+                if (f->equal(qp, qp_in)) {
+                        atomic_inc(&qp->refcnt);
+                        write_unlock(&f->lock);
+                        qp_in->last_in |= COMPLETE;
+                        inet_frag_put(qp_in, f);
+                        return qp;
+                }
+        }
+#endif
+        qp = qp_in;
+        if (!mod_timer(&qp->timer, jiffies + f->ctl->timeout))
+                atomic_inc(&qp->refcnt);
+
+        atomic_inc(&qp->refcnt);
+        hlist_add_head(&qp->list, &f->hash[hash]);
+        list_add_tail(&qp->lru_list, &f->lru_list);
+        f->nqueues++;
+        write_unlock(&f->lock);
+        return qp;
+}
+EXPORT_SYMBOL(inet_frag_intern);