SCTP: Use hashed lookup when looking for an association.

A SCTP endpoint may have a lot of associations on them and walking
the list is fairly inefficient.  Instead, use a hashed lookup,
and filter out the hash list based on the endopoing we already have.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index 2d2d81e..68f0556 100644 (file)
--- a/net/sctp/endpointola.c
+++ b/net/sctp/endpointola.c
@@ -328,24 +328,34 @@ static struct sctp_association *__sctp_endpoint_lookup_assoc(
        const union sctp_addr *paddr,
        struct sctp_transport **transport)
 {
+       struct sctp_association *asoc = NULL;
+       struct sctp_transport *t = NULL;
+       struct sctp_hashbucket *head;
+       struct sctp_ep_common *epb;
+       int hash;
        int rport;
-       struct sctp_association *asoc;
-       struct list_head *pos;
 
+       *transport = NULL;
        rport = ntohs(paddr->v4.sin_port);
 
-       list_for_each(pos, &ep->asocs) {
-               asoc = list_entry(pos, struct sctp_association, asocs);
-               if (rport == asoc->peer.port) {
-                       *transport = sctp_assoc_lookup_paddr(asoc, paddr);
-
-                       if (*transport)
-                               return asoc;
+       hash = sctp_assoc_hashfn(ep->base.bind_addr.port, rport);
+       head = &sctp_assoc_hashtable[hash];
+       read_lock(&head->lock);
+       for (epb = head->chain; epb; epb = epb->next) {
+               asoc = sctp_assoc(epb);
+               if (asoc->ep != ep || rport != asoc->peer.port)
+                       goto next;
+
+               t = sctp_assoc_lookup_paddr(asoc, paddr);
+               if (t) {
+                       *transport = t;
+                       break;
                }
+next:
+               asoc = NULL;
        }
-
-       *transport = NULL;
-       return NULL;
+       read_unlock(&head->lock);
+       return asoc;
 }
 
 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */