6 files changed, 47 insertions, 20 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);
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 3b9f09d55b5c..b38bf69310ee 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -543,10 +543,15 @@ struct compat_ethtool_rxnfc {
 /**
  * struct ethtool_rxfh_indir - command to get or set RX flow hash indirection
  * @cmd: Specific command number - %ETHTOOL_GRXFHINDIR or %ETHTOOL_SRXFHINDIR
- * @size: On entry, the array size of the user buffer, which may be zero
- *      for %ETHTOOL_GRXFHINDIR.  On return from %ETHTOOL_GRXFHINDIR, the
- *      array size of the hardware indirection table.
+ * @size: On entry, the array size of the user buffer, which may be zero.
+ *      On return from %ETHTOOL_GRXFHINDIR, the array size of the hardware
+ *      indirection table.
  * @ring_index: RX ring/queue index for each hash value
+ *
+ * For %ETHTOOL_GRXFHINDIR, a @size of zero means that only the size
+ * should be returned.  For %ETHTOOL_SRXFHINDIR, a @size of zero means
+ * the table should be reset to default values.  This last feature
+ * is not supported by the original implementations.
  */
 struct ethtool_rxfh_indir {
         __u32   cmd;
@@ -750,6 +755,18 @@ struct net_device;
 u32 ethtool_op_get_link(struct net_device *dev);
 
 /**
+ * ethtool_rxfh_indir_default - get default value for RX flow hash indirection
+ * @index: Index in RX flow hash indirection table
+ * @n_rx_rings: Number of RX rings to use
+ *
+ * This function provides the default policy for RX flow hash indirection.
+ */
+static inline u32 ethtool_rxfh_indir_default(u32 index, u32 n_rx_rings)
+{
+        return index % n_rx_rings;
+}
+
+/**
  * struct ethtool_ops - optional netdev operations
  * @get_settings: Get various device settings including Ethernet link
  *      settings. The @cmd parameter is expected to have been cleared
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 69f71b86b035..597732c989ca 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -581,31 +581,38 @@ static noinline_for_stack int ethtool_set_rxfh_indir(struct net_device *dev,
                            sizeof(user_size)))
                 return -EFAULT;
 
-        if (user_size != dev_size)
+        if (user_size != 0 && user_size != dev_size)
                 return -EINVAL;
 
         indir = kcalloc(dev_size, sizeof(indir[0]), GFP_USER);
         if (!indir)
                 return -ENOMEM;
 
-        if (copy_from_user(indir,
-                           useraddr +
-                           offsetof(struct ethtool_rxfh_indir, ring_index[0]),
-                           dev_size * sizeof(indir[0]))) {
-                ret = -EFAULT;
-                goto out;
-        }
-
-        /* Validate ring indices */
         rx_rings.cmd = ETHTOOL_GRXRINGS;
         ret = dev->ethtool_ops->get_rxnfc(dev, &rx_rings, NULL);
         if (ret)
                 goto out;
-        for (i = 0; i < dev_size; i++) {
-                if (indir[i] >= rx_rings.data) {
-                        ret = -EINVAL;
+
+        if (user_size == 0) {
+                for (i = 0; i < dev_size; i++)
+                        indir[i] = ethtool_rxfh_indir_default(i, rx_rings.data);
+        } else {
+                if (copy_from_user(indir,
+                                  useraddr +
+                                  offsetof(struct ethtool_rxfh_indir,
+                                           ring_index[0]),
+                                  dev_size * sizeof(indir[0]))) {
+                        ret = -EFAULT;
                         goto out;
                 }
+
+                /* Validate ring indices */
+                for (i = 0; i < dev_size; i++) {
+                        if (indir[i] >= rx_rings.data) {
+                                ret = -EINVAL;
+                                goto out;
+                        }
+                }
         }
 
         ret = dev->ethtool_ops->set_rxfh_indir(dev, indir);