[dpdk-dev] [PATCH v1] net/mlx4: fix single port configuration

[Ophir Munk <ophirmu@mellanox.com>]

The number of mlx4 present ports is calculated as follows:
conf.ports.present |= (UINT64_C(1) << device_attr.phys_port_cnt) - 1;

That is - all ones sequence (due to -1 subtraction)
When retrieving the number of ports, 1 must be added in order to obtain
the correct number of ports to the power of 2, as follows:
uint32_t ports = rte_log2_u32(conf->ports.present + 1);
If 1 was not added, in the case of one port, the number of ports would
be falsely calculated as 0.

Fixes: 82642799 ("net/mlx4: check max number of ports dynamically")
Cc: stable@dpdk.org

Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
---
 drivers/net/mlx4/mlx4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 2a721e7..952dae0 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -337,7 +337,7 @@ mlx4_arg_parse(const char *key, const char *val, struct mlx4_conf *conf)
 		return -rte_errno;
 	}
 	if (strcmp(MLX4_PMD_PORT_KVARG, key) == 0) {
-		uint32_t ports = rte_log2_u32(conf->ports.present);
+		uint32_t ports = rte_log2_u32(conf->ports.present + 1);
 
 		if (tmp >= ports) {
 			ERROR("port index %lu outside range [0,%" PRIu32 ")",
-- 
2.7.4