net: ethtool: add a NO_CHANGE uAPI for new RXFH's input_xfrm

Add a NO_CHANGE uAPI value for the new RXFH/RSS input_xfrm uAPI field.
This needed so that user-space can set other RSS values (hkey or indir
table) without affecting input_xfrm.

Should have been part of [1].

Link: https://lore.kernel.org/netdev/20231213003321.605376-1-ahmed.zaki@intel.com/
Fixes: 13e59344fb9d ("net: ethtool: add support for symmetric-xor RSS hash")
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
Link: https://lore.kernel.org/r/20231221184235.9192-3-ahmed.zaki@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 60801df9d8c0e47f226a5057cb31e648242ee3d9..01ba529dbb6db22bb700682f81e2b3ab751ac347 100644 (file)
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -2002,6 +2002,7 @@ static inline int ethtool_validate_duplex(__u8 duplex)
  * be exploited to reduce the RSS queue spread.
  */
 #define        RXH_XFRM_SYM_XOR        (1 << 0)
+#define        RXH_XFRM_NO_CHANGE      0xff
 
 /* L2-L4 network traffic flow types */
 #define        TCP_V4_FLOW     0x01    /* hash or spec (tcp_ip4_spec) */

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 9adc240b8f0eb0ce9858c174e9592b93a4d5341a..4c4f46dfc251b82b2cf350495e7f6e13a77a850e 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1304,14 +1304,16 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
                return -EOPNOTSUPP;
 
        /* If either indir, hash key or function is valid, proceed further.
-        * Must request at least one change: indir size, hash key or function.
+        * Must request at least one change: indir size, hash key, function
+        * or input transformation.
         */
        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.hfunc == ETH_RSS_HASH_NO_CHANGE))
+            rxfh.key_size == 0 && rxfh.hfunc == ETH_RSS_HASH_NO_CHANGE &&
+            rxfh.input_xfrm == RXH_XFRM_NO_CHANGE))
                return -EINVAL;
 
        if (rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE)