ethtool: Centralise validation of ETHTOOL_{G, S}RXFHINDIR parameters

Add a new ethtool operation (get_rxfh_indir_size) to get the
indirectional table size.  Use this to validate the user buffer size
before calling get_rxfh_indir or set_rxfh_indir.  Use get_rxnfc to get
the number of RX rings, and validate the contents of the new
indirection table before calling set_rxfh_indir.  Remove this
validation from drivers.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Dimitris Michailidis <dm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 0ec2fd412d03..3b9f09d55b5c 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -828,9 +828,13 @@ u32 ethtool_op_get_link(struct net_device *dev);
  *      error code or zero.
  * @set_rx_ntuple: Set an RX n-tuple rule.  Returns a negative error code
  *      or zero.
+ * @get_rxfh_indir_size: Get the size of the RX flow hash indirection table.
+ *      Returns zero if not supported for this specific device.
  * @get_rxfh_indir: Get the contents of the RX flow hash indirection table.
+ *      Will not be called if @get_rxfh_indir_size returns 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.
  *      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
@@ -894,10 +898,9 @@ struct ethtool_ops {
         int     (*reset)(struct net_device *, u32 *);
         int     (*set_rx_ntuple)(struct net_device *,
                                  struct ethtool_rx_ntuple *);
-        int     (*get_rxfh_indir)(struct net_device *,
-                                  struct ethtool_rxfh_indir *);
-        int     (*set_rxfh_indir)(struct net_device *,
-                                  const struct ethtool_rxfh_indir *);
+        u32     (*get_rxfh_indir_size)(struct net_device *);
+        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 *);
         int     (*set_channels)(struct net_device *, struct ethtool_channels *);
         int     (*get_dump_flag)(struct net_device *, struct ethtool_dump *);