datapath: Avoid calling flow_hash() twice for the same key.

This is a small optimization for the case where a new flow is being added
to the flow table.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index cf16323..b95c8f2 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -817,9 +817,11 @@ static int do_put_flow(struct datapath *dp, struct odp_flow_put *uf,
        struct sw_flow *flow;
        struct tbl *table;
        int error;
+       u32 hash;
 
+       hash = flow_hash(&uf->flow.key);
        table = get_table_protected(dp);
-       flow_node = tbl_lookup(table, &uf->flow.key, flow_hash(&uf->flow.key), flow_cmp);
+       flow_node = tbl_lookup(table, &uf->flow.key, hash, flow_cmp);
        if (!flow_node) {
                /* No such flow. */
                struct sw_flow_actions *acts;
@@ -853,7 +855,7 @@ static int do_put_flow(struct datapath *dp, struct odp_flow_put *uf,
                rcu_assign_pointer(flow->sf_acts, acts);
 
                /* Put flow in bucket. */
-               error = tbl_insert(table, &flow->tbl_node, flow_hash(&flow->key));
+               error = tbl_insert(table, &flow->tbl_node, hash);
                if (error)
                        goto error_free_flow_acts;