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From:   Ivan Vecera <ivecera@redhat.com>
To:     netdev@vger.kernel.org
Cc:     Tianhao <tizhao@redhat.com>,
        Sathya Perla <sathya.perla@broadcom.com>,
        Ajit Khaparde <ajit.khaparde@broadcom.com>,
        Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>,
        Somnath Kotur <somnath.kotur@broadcom.com>,
        "David S. Miller" <davem@davemloft.net>,
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH net] be2net: Fix number of Rx queues used for flow hashing
Date:   Fri, 14 Jun 2019 17:48:36 +0200
Message-Id: <20190614154836.22172-1-ivecera@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Number of Rx queues used for flow hashing returned by the driver is
incorrect and this bug prevents user to use the last Rx queue in
indirection table.

Let's say we have a NIC with 6 combined queues:

[root@sm-03 ~]# ethtool -l enp4s0f0
Channel parameters for enp4s0f0:
Pre-set maximums:
RX:             5
TX:             5
Other:          0
Combined:       6
Current hardware settings:
RX:             0
TX:             0
Other:          0
Combined:       6

Default indirection table maps all (6) queues equally but the driver
reports only 5 rings available.

[root@sm-03 ~]# ethtool -x enp4s0f0
RX flow hash indirection table for enp4s0f0 with 5 RX ring(s):
    0:      0     1     2     3     4     5     0     1
    8:      2     3     4     5     0     1     2     3
   16:      4     5     0     1     2     3     4     5
   24:      0     1     2     3     4     5     0     1
...

Now change indirection table somehow:

[root@sm-03 ~]# ethtool -X enp4s0f0 weight 1 1
[root@sm-03 ~]# ethtool -x enp4s0f0
RX flow hash indirection table for enp4s0f0 with 6 RX ring(s):
    0:      0     0     0     0     0     0     0     0
...
   64:      1     1     1     1     1     1     1     1
...

Now it is not possible to change mapping back to equal (default) state:

[root@sm-03 ~]# ethtool -X enp4s0f0 equal 6
Cannot set RX flow hash configuration: Invalid argument

Fixes: 594ad54a2c3b ("be2net: Add support for setting and getting rx flow hash options")
Reported-by: Tianhao <tizhao@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
 drivers/net/ethernet/emulex/benet/be_ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/emulex/benet/be_ethtool.c b/drivers/net/ethernet/emulex/benet/be_ethtool.c
index 4c218341c51b..6e635debc7fd 100644
--- a/drivers/net/ethernet/emulex/benet/be_ethtool.c
+++ b/drivers/net/ethernet/emulex/benet/be_ethtool.c
@@ -1105,7 +1105,7 @@ static int be_get_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *cmd,
 		cmd->data = be_get_rss_hash_opts(adapter, cmd->flow_type);
 		break;
 	case ETHTOOL_GRXRINGS:
-		cmd->data = adapter->num_rx_qs - 1;
+		cmd->data = adapter->num_rx_qs;
 		break;
 	default:
 		return -EINVAL;
-- 
2.21.0