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>
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 3b9f09d..b38bf69 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -543,10 +543,15 @@
/**
* 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 @@
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