Re: [net-next-2.6 PATCH] ethtool: update get_rx_ntuple to correctly interpret string count

On 1/4/2011 4:01 PM, Ben Hutchings wrote:

On Tue, 2011-01-04 at 15:29 -0800, Alexander Duyck wrote:

quoted

Currently any strings returned via the get_rx_ntuple call will just be
dropped because the num_strings will be zero.  In order to correct this I
am updating things so that the return value of get_rx_ntuple is the number
of strings that were written, or a negative value if there was an error.

[...]

Nothing implements ethtool_ops::get_rx_ntuple, anyway.

The fallback implementation is totally bogus, too.  Maximum of 1024
filters?  Erm, sfc can handle more than that.  And doing complex string
formatting in the kernel, even though all the parsing is in ethtool?

Please, let's write off ETHTOOL_GRXNTUPLE as a failed experiment and
replace it with a command that behaves more like ETHTOOL_GRXCLSRLALL.

Ben.

In order to address several different issues in the perfect filters provided by 82599 I found it necessary to implement get_rx_ntuple so that the driver could maintain the filter list inside of the driver instead of having it maintained by the stack.  In doing so though I found the bug.

I agree the fallback implementation has a limitation on the number and format of filters it supports.  However declaring the function a "failed experiment" and just dropping it isn't exactly constructive since we have customers that are making use of the feature.  The fallback implementation is meant to be just that, and the patch I provided makes it possible to support more filters if needed by implementing a means of tracking/displaying the filters within the driver itself.

Thanks,

Alex