When using RSS, the number of rxqs has to be a power of two.
This is a problem because there is no API is dpdk that makes
the application aware of that.

A good compromise is to allow the application to request a
number of rxqs that is not a power of 2, but having inactive
queues that will never receive packets. In this configuration,
a warning will be issued to users to let them know that
this is not an optimal configuration.

Signed-off-by: Olivier Matz <redacted>
---
 drivers/net/mlx4/mlx4.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index cc4e9aa..eaf06db 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c

@@ -698,7 +698,7 @@ txq_cleanup(struct txq *txq);
 
 static int
 rxq_setup(struct rte_eth_dev *dev, struct rxq *rxq, uint16_t desc,
-	  unsigned int socket, const struct rte_eth_rxconf *conf,
+	  unsigned int socket, int inactive, const struct rte_eth_rxconf *conf,
 	  struct rte_mempool *mp);
 
 static void

@@ -734,12 +734,12 @@ dev_configure(struct rte_eth_dev *dev)
 	}
 	if (rxqs_n == priv->rxqs_n)
 		return 0;
-	if ((rxqs_n & (rxqs_n - 1)) != 0) {
-		ERROR("%p: invalid number of RX queues (%u),"
-		      " must be a power of 2",
+	if (!rte_is_power_of_2(rxqs_n)) {
+		WARN("%p: number of RX queues (%u), must be a"
+		      " power of 2: remaining queues will be inactive",