mlx5: fix hash Rx queue type in RSS mode

Only seen since IPv6 RSS support was added, confusion about the purpose of
the hash_rxq_type_from_n() function has caused it to return invalid hash RX
queue types.

Refactor function for its intended purpose, rename it
hash_rxq_type_from_pos() and update comment with a better description.

Fixes: a76133214d88 ("mlx5: use separate indirection table for default hash Rx queue")

Reported-by: Olga Shern <olgas@mellanox.com>
Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 3d7ae7e..37b4efd 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -259,23 +259,29 @@ hash_rxq_flow_attr(const struct hash_rxq *hash_rxq,
 }
 
 /**
- * Return the type corresponding to the n'th bit set.
+ * Convert hash type position in indirection table initializer to
+ * hash RX queue type.
  *
  * @param table
- *   The indirection table.
- * @param n
- *   The n'th bit set.
+ *   Indirection table initializer.
+ * @param pos
+ *   Hash type position.
  *
  * @return
- *   The corresponding hash_rxq_type.
+ *   Hash RX queue type.
  */
 static enum hash_rxq_type
-hash_rxq_type_from_n(const struct ind_table_init *table, unsigned int n)
+hash_rxq_type_from_pos(const struct ind_table_init *table, unsigned int pos)
 {
-       assert(n < table->hash_types_n);
-       while (((table->hash_types >> n) & 0x1) == 0)
-               ++n;
-       return n;
+       enum hash_rxq_type type = 0;
+
+       assert(pos < table->hash_types_n);
+       do {
+               if ((table->hash_types & (1 << type)) && (pos-- == 0))
+                       break;
+               ++type;
+       } while (1);
+       return type;
 }
 
 /**
@@ -429,7 +435,7 @@ priv_create_hash_rxqs(struct priv *priv)
             ++i) {
                struct hash_rxq *hash_rxq = &(*hash_rxqs)[i];
                enum hash_rxq_type type =
-                       hash_rxq_type_from_n(&ind_table_init[j], k);
+                       hash_rxq_type_from_pos(&ind_table_init[j], k);
                struct rte_eth_rss_conf *priv_rss_conf =
                        (*priv->rss_conf)[type];
                struct ibv_exp_rx_hash_conf hash_conf = {
@@ -453,8 +459,8 @@ priv_create_hash_rxqs(struct priv *priv)
                        .port_num = priv->port,
                };
 
-               DEBUG("using indirection table %u for hash RX queue %u",
-                     j, i);
+               DEBUG("using indirection table %u for hash RX queue %u type %d",
+                     j, i, type);
                *hash_rxq = (struct hash_rxq){
                        .priv = priv,
                        .qp = ibv_exp_create_qp(priv->ctx, &qp_init_attr),