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>

1 files changed, 22 insertions, 12 deletions

diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index 2d2d81ef4a69..68f0556efcc6 100644
--- 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.  */