ethtool: Expand documentation of ethtool_ops::{get,set}_rxfh()

Some corner-cases are not explained properly.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 212f537fc686a8384c7618e97f5e02cdea5f524c..886e127d51a6153b90b2826fafb95a70150fccc0 100644 (file)
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -162,15 +162,16 @@ static inline u32 ethtool_rxfh_indir_default(u32 index, u32 n_rx_rings)
  *     Will not be called if @get_rxfh_indir_size returns zero.
  * @get_rxfh: Get the contents of the RX flow hash indirection table and hash
  *     key.
- *     Will not be called if @get_rxfh_indir_size and @get_rxfh_key_size
- *     returns zero.
+ *     Will only be called if one or both of @get_rxfh_indir_size and
+ *     @get_rxfh_key_size are implemented and return non-zero.
  *     Returns a negative error code or zero.
  * @set_rxfh_indir: Set the contents of the RX flow hash indirection table.
  *     Will not be called if @get_rxfh_indir_size returns zero.
- * @set_rxfh: Set the contents of the RX flow hash indirection table and
- *     hash key.
- *     Will not be called if @get_rxfh_indir_size and @get_rxfh_key_size
- *     returns zero.
+ * @set_rxfh: Set the contents of the RX flow hash indirection table and/or
+ *     hash key.  Either or both arguments may be %NULL if that attribute
+ *     is not to be changed.
+ *     Will only be called if one or both of @get_rxfh_indir_size and
+ *     @get_rxfh_key_size are implemented and return non-zero.
  *     Returns a negative error code or zero.
  * @get_channels: Get number of channels.
  * @set_channels: Set number of channels.  Returns a negative error code or
@@ -244,8 +245,8 @@ struct ethtool_ops {
        int     (*reset)(struct net_device *, u32 *);
        u32     (*get_rxfh_key_size)(struct net_device *);
        u32     (*get_rxfh_indir_size)(struct net_device *);
-       int     (*get_rxfh)(struct net_device *, u32 *, u8 *);
-       int     (*set_rxfh)(struct net_device *, u32 *, u8 *);
+       int     (*get_rxfh)(struct net_device *, u32 *indir, u8 *key);
+       int     (*set_rxfh)(struct net_device *, u32 *indir, u8 *key);
        int     (*get_rxfh_indir)(struct net_device *, u32 *);
        int     (*set_rxfh_indir)(struct net_device *, const u32 *);
        void    (*get_channels)(struct net_device *, struct ethtool_channels *);