On Mon, 2014-09-29 at 15:47 +0800, Fugang Duan wrote:

- Copy short frames and keep the buffers mapped, re-allocate skb instead of
  memory copy for long frames.
- Add support for setting/getting rx_copybreak using generic ethtool tunable

Changes V2:
* Implements rx_copybreak

 
+#define COPYBREAK_DEFAULT 256
+static unsigned int copybreak __read_mostly = COPYBREAK_DEFAULT;
+module_param(copybreak, uint, 0644);
+MODULE_PARM_DESC(copybreak,
+		 "Maximum packet size that is copied to a new buffer on receive");
+

It is not the right way to handle this.

Old drivers might still have a legacy module parameter.

New implementations should provide the new ethtool support, and only
this. No new module parameter is accepted.

For details, check following commits :

d4ad30b182305ecf97f145a5d4d1fd9e728c6d01 enic: Add tunable_ops support
for rx_copybreak

f0db9b073415848709dd59a6394969882f517da9 ethtool: Add generic options
for tunables


Or check the current tree :

git grep -n rx_copybreak drivers/net/ethernet/cisco/enic