ethtool: Define and apply a default policy for RX flow hash indirection

All drivers that support modification of the RX flow hash indirection
table initialise it in the same way: RX rings are assigned to table
entries in rotation.  Make that default policy explicit by having them
call a ethtool_rxfh_indir_default() function.

In the ethtool core, add support for a zero size value for
ETHTOOL_SRXFHINDIR, which resets the table to this default.

Partly-suggested-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Shreyas N Bhatewara <sbhatewara@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 7 insertions, 4 deletions

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 64f5cf5c68d1..2b731b253598 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -1545,7 +1545,8 @@ static inline int bnx2x_init_rss_pf(struct bnx2x *bp)
         if (bp->multi_mode != ETH_RSS_MODE_DISABLED) {
                 for (i = 0; i < sizeof(ind_table); i++)
                         ind_table[i] =
-                                bp->fp->cl_id + (i % num_eth_queues);
+                                bp->fp->cl_id +
+                                ethtool_rxfh_indir_default(i, num_eth_queues);
         }
 
         /*
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index 8ffd55bdef3d..fccbe490c7f0 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -3449,7 +3449,7 @@ static int __devinit init_rss(struct adapter *adap)
                 if (!pi->rss)
                         return -ENOMEM;
                 for (j = 0; j < pi->rss_size; j++)
-                        pi->rss[j] = j % pi->nqsets;
+                        pi->rss[j] = ethtool_rxfh_indir_default(j, pi->nqsets);
         }
         return 0;
 }
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 14e134d3b4d7..44a82c6c60a7 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -1336,7 +1336,8 @@ static int efx_probe_nic(struct efx_nic *efx)
         if (efx->n_channels > 1)
                 get_random_bytes(&efx->rx_hash_key, sizeof(efx->rx_hash_key));
         for (i = 0; i < ARRAY_SIZE(efx->rx_indir_table); i++)
-                efx->rx_indir_table[i] = i % efx->n_rx_channels;
+                efx->rx_indir_table[i] =
+                        ethtool_rxfh_indir_default(i, efx->n_rx_channels);
 
         efx_set_channels(efx);
         netif_set_real_num_tx_queues(efx->net_dev, efx->n_tx_channels);
diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 1c2ae11a9e35..de7fc345148a 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2167,7 +2167,8 @@ vmxnet3_setup_driver_shared(struct vmxnet3_adapter *adapter)
                 rssConf->indTableSize = VMXNET3_RSS_IND_TABLE_SIZE;
                 get_random_bytes(&rssConf->hashKey[0], rssConf->hashKeySize);
                 for (i = 0; i < rssConf->indTableSize; i++)
-                        rssConf->indTable[i] = i % adapter->num_rx_queues;
+                        rssConf->indTable[i] = ethtool_rxfh_indir_default(
+                                i, adapter->num_rx_queues);
 
                 devRead->rssConfDesc.confVer = 1;
                 devRead->rssConfDesc.confLen = sizeof(*rssConf);