ethtool: Support for configurable RSS hash function

This patch extends the set/get_rxfh ethtool-options for getting or
setting the RSS hash function.

It modifies drivers implementation of set/get_rxfh accordingly.

This change also delegates the responsibility of checking whether a
modification to a certain RX flow hash parameter is supported to the
driver implementation of set_rxfh.

User-kernel API is done through the new hfunc bitmask field in the
ethtool_rxfh struct. A bit set in the hfunc field is corresponding to an
index in the new string-set ETH_SS_RSS_HASH_FUNCS.

Got approval from most of the relevant driver maintainers that their
driver is using Toeplitz, and for the few that didn't answered, also
assumed it is Toeplitz.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Ariel Elior <ariel.elior@qlogic.com>
Cc: Prashant Sreedharan <prashant@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Bruce Allan <bruce.w.allan@intel.com>
Cc: Carolyn Wyborny <carolyn.wyborny@intel.com>
Cc: Don Skidmore <donald.c.skidmore@intel.com>
Cc: Greg Rose <gregory.v.rose@intel.com>
Cc: Matthew Vick <matthew.vick@intel.com>
Cc: John Ronciak <john.ronciak@intel.com>
Cc: Mitch Williams <mitch.a.williams@intel.com>
Cc: Amir Vadai <amirv@mellanox.com>
Cc: Solarflare linux maintainers <linux-net-drivers@solarflare.com>
Cc: Shradha Shah <sshah@solarflare.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Cc: "VMware, Inc." <pv-drivers@vmware.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 32 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 715f51f321e9..550892cd6b3f 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -100,6 +100,12 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
         [NETIF_F_BUSY_POLL_BIT] =        "busy-poll",
 };
 
+static const char
+rss_hash_func_strings[ETH_RSS_HASH_FUNCS_COUNT][ETH_GSTRING_LEN] = {
+        [ETH_RSS_HASH_TOP_BIT] =        "toeplitz",
+        [ETH_RSS_HASH_XOR_BIT] =        "xor",
+};
+
 static int ethtool_get_features(struct net_device *dev, void __user *useraddr)
 {
         struct ethtool_gfeatures cmd = {
@@ -185,6 +191,9 @@ static int __ethtool_get_sset_count(struct net_device *dev, int sset)
         if (sset == ETH_SS_FEATURES)
                 return ARRAY_SIZE(netdev_features_strings);
 
+        if (sset == ETH_SS_RSS_HASH_FUNCS)
+                return ARRAY_SIZE(rss_hash_func_strings);
+
         if (ops->get_sset_count && ops->get_strings)
                 return ops->get_sset_count(dev, sset);
         else
@@ -199,6 +208,9 @@ static void __ethtool_get_strings(struct net_device *dev,
         if (stringset == ETH_SS_FEATURES)
                 memcpy(data, netdev_features_strings,
                         sizeof(netdev_features_strings));
+        else if (stringset == ETH_SS_RSS_HASH_FUNCS)
+                memcpy(data, rss_hash_func_strings,
+                       sizeof(rss_hash_func_strings));
         else
                 /* ops->get_strings is valid because checked earlier */
                 ops->get_strings(dev, stringset, data);
@@ -618,7 +630,7 @@ static noinline_for_stack int ethtool_get_rxfh_indir(struct net_device *dev,
         if (!indir)
                 return -ENOMEM;
 
-        ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL);
+        ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL, NULL);
         if (ret)
                 goto out;
 
@@ -679,7 +691,7 @@ static noinline_for_stack int ethtool_set_rxfh_indir(struct net_device *dev,
                         goto out;
         }
 
-        ret = ops->set_rxfh(dev, indir, NULL);
+        ret = ops->set_rxfh(dev, indir, NULL, ETH_RSS_HASH_NO_CHANGE);
 
 out:
         kfree(indir);
@@ -697,12 +709,11 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
         u32 total_size;
         u32 indir_bytes;
         u32 *indir = NULL;
+        u8 dev_hfunc = 0;
         u8 *hkey = NULL;
         u8 *rss_config;
 
-        if (!(dev->ethtool_ops->get_rxfh_indir_size ||
-              dev->ethtool_ops->get_rxfh_key_size) ||
-              !dev->ethtool_ops->get_rxfh)
+        if (!ops->get_rxfh)
                 return -EOPNOTSUPP;
 
         if (ops->get_rxfh_indir_size)
@@ -710,16 +721,14 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
         if (ops->get_rxfh_key_size)
                 dev_key_size = ops->get_rxfh_key_size(dev);
 
-        if ((dev_key_size + dev_indir_size) == 0)
-                return -EOPNOTSUPP;
-
         if (copy_from_user(&rxfh, useraddr, sizeof(rxfh)))
                 return -EFAULT;
         user_indir_size = rxfh.indir_size;
         user_key_size = rxfh.key_size;
 
         /* Check that reserved fields are 0 for now */
-        if (rxfh.rss_context || rxfh.rsvd[0] || rxfh.rsvd[1])
+        if (rxfh.rss_context || rxfh.rsvd8[0] || rxfh.rsvd8[1] ||
+            rxfh.rsvd8[2] || rxfh.rsvd32)
                 return -EINVAL;
 
         rxfh.indir_size = dev_indir_size;
@@ -727,13 +736,6 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
         if (copy_to_user(useraddr, &rxfh, sizeof(rxfh)))
                 return -EFAULT;
 
-        /* If the user buffer size is 0, this is just a query for the
-         * device table size and key size.  Otherwise, if the User size is
-         * not equal to device table size or key size it's an error.
-         */
-        if (!user_indir_size && !user_key_size)
-                return 0;
-
         if ((user_indir_size && (user_indir_size != dev_indir_size)) ||
             (user_key_size && (user_key_size != dev_key_size)))
                 return -EINVAL;
@@ -750,14 +752,19 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
         if (user_key_size)
                 hkey = rss_config + indir_bytes;
 
-        ret = dev->ethtool_ops->get_rxfh(dev, indir, hkey);
-        if (!ret) {
-                if (copy_to_user(useraddr +
-                                 offsetof(struct ethtool_rxfh, rss_config[0]),
-                                 rss_config, total_size))
-                        ret = -EFAULT;
-        }
+        ret = dev->ethtool_ops->get_rxfh(dev, indir, hkey, &dev_hfunc);
+        if (ret)
+                goto out;
 
+        if (copy_to_user(useraddr + offsetof(struct ethtool_rxfh, hfunc),
+                         &dev_hfunc, sizeof(rxfh.hfunc))) {
+                ret = -EFAULT;
+        } else if (copy_to_user(useraddr +
+                              offsetof(struct ethtool_rxfh, rss_config[0]),
+                              rss_config, total_size)) {
+                ret = -EFAULT;
+        }
+out:
         kfree(rss_config);
 
         return ret;
@@ -776,33 +783,31 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
         u8 *rss_config;
         u32 rss_cfg_offset = offsetof(struct ethtool_rxfh, rss_config[0]);
 
-        if (!(ops->get_rxfh_indir_size || ops->get_rxfh_key_size) ||
-            !ops->get_rxnfc || !ops->set_rxfh)
+        if (!ops->get_rxnfc || !ops->set_rxfh)
                 return -EOPNOTSUPP;
 
         if (ops->get_rxfh_indir_size)
                 dev_indir_size = ops->get_rxfh_indir_size(dev);
         if (ops->get_rxfh_key_size)
                 dev_key_size = dev->ethtool_ops->get_rxfh_key_size(dev);
-        if ((dev_key_size + dev_indir_size) == 0)
-                return -EOPNOTSUPP;
 
         if (copy_from_user(&rxfh, useraddr, sizeof(rxfh)))
                 return -EFAULT;
 
         /* Check that reserved fields are 0 for now */
-        if (rxfh.rss_context || rxfh.rsvd[0] || rxfh.rsvd[1])
+        if (rxfh.rss_context || rxfh.rsvd8[0] || rxfh.rsvd8[1] ||
+            rxfh.rsvd8[2] || rxfh.rsvd32)
                 return -EINVAL;
 
-        /* If either indir or hash key is valid, proceed further.
-         * It is not valid to request that both be unchanged.
+        /* If either indir, hash key or function is valid, proceed further.
+         * Must request at least one change: indir size, hash key or function.
          */
         if ((rxfh.indir_size &&
              rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE &&
              rxfh.indir_size != dev_indir_size) ||
             (rxfh.key_size && (rxfh.key_size != dev_key_size)) ||
             (rxfh.indir_size == ETH_RXFH_INDIR_NO_CHANGE &&
-             rxfh.key_size == 0))
+             rxfh.key_size == 0 && rxfh.hfunc == ETH_RSS_HASH_NO_CHANGE))
                 return -EINVAL;
 
         if (rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE)
@@ -845,7 +850,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
                 }
         }
 
-        ret = ops->set_rxfh(dev, indir, hkey);
+        ret = ops->set_rxfh(dev, indir, hkey, rxfh.hfunc);
 
 out:
         kfree(rss_config);