net/mlx4: add RSS support outside flow API

Bring back support for automatic RSS with the default flow rules when not
in isolated mode. Balancing is done according to unspecified default
settings, as was the case before this entire rework.

Since the number of queues part of RSS contexts is limited to power of two
values, the number of configured queues is rounded down to its previous
power of two; extra queues are silently discarded. This does not prevent
dedicated flow rules from targeting them.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

diff --git a/drivers/net/mlx4/mlx4_flow.c b/drivers/net/mlx4/mlx4_flow.c
index 4c498f0bee4f9903d7fb2f4528942589f9deef28..5c4bf8e191fac41a3d9a1a92bd1bd329fc226ecf 100644 (file)
--- a/drivers/net/mlx4/mlx4_flow.c
+++ b/drivers/net/mlx4/mlx4_flow.c
@@ -1256,12 +1256,21 @@ mlx4_flow_internal(struct priv *priv, struct rte_flow_error *error)
                        .type = RTE_FLOW_ITEM_TYPE_END,
                },
        };
+       /*
+        * Round number of queues down to their previous power of 2 to
+        * comply with RSS context limitations. Extra queues silently do not
+        * get RSS by default.
+        */
+       uint32_t queues =
+               rte_align32pow2(priv->dev->data->nb_rx_queues + 1) >> 1;
+       alignas(struct rte_flow_action_rss) uint8_t rss_conf_data
+               [offsetof(struct rte_flow_action_rss, queue) +
+                sizeof(((struct rte_flow_action_rss *)0)->queue[0]) * queues];
+       struct rte_flow_action_rss *rss_conf = (void *)rss_conf_data;
        struct rte_flow_action actions[] = {
                {
-                       .type = RTE_FLOW_ACTION_TYPE_QUEUE,
-                       .conf = &(struct rte_flow_action_queue){
-                               .index = 0,
-                       },
+                       .type = RTE_FLOW_ACTION_TYPE_RSS,
+                       .conf = rss_conf,
                },
                {
                        .type = RTE_FLOW_ACTION_TYPE_END,
@@ -1281,6 +1290,13 @@ mlx4_flow_internal(struct priv *priv, struct rte_flow_error *error)
        unsigned int i;
        int err = 0;
 
+       /* Prepare default RSS configuration. */
+       *rss_conf = (struct rte_flow_action_rss){
+               .rss_conf = NULL, /* Rely on default fallback settings. */
+               .num = queues,
+       };
+       for (i = 0; i != queues; ++i)
+               rss_conf->queue[i] = i;
        /*
         * Set up VLAN item if filtering is enabled and at least one VLAN
         * filter is configured.