Re: [PATCH net v2 1/2] net: ethtool: Don't check if RSS context exists in case of context 0

[Subbaraya Sundeep <sbhatta@marvell.com>]

On 2025-06-09 at 12:02:49, Gal Pressman (gal@nvidia.com) wrote:
> Context 0 (default context) always exists, there is no need to check
> whether it exists or not when adding a flow steering rule.
> 
> The existing check fails when creating a flow steering rule for context
> 0 as it is not stored in the rss_ctx xarray.
> 
> For example:
> $ ethtool --config-ntuple eth2 flow-type tcp4 dst-ip 194.237.147.23 dst-port 19983 context 0 loc 618
> rmgr: Cannot insert RX class rule: Invalid argument
> Cannot insert classification rule
> 
> An example usecase for this could be:
> - A high-priority rule (loc 0) directing specific port traffic to
>   context 0.
> - A low-priority rule (loc 1) directing all other TCP traffic to context
>   1.
> 
> Fixes: de7f7582dff2 ("net: ethtool: prevent flow steering to RSS contexts which don't exist")
> Cc: Jakub Kicinski <kuba@kernel.org>
> Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
> Reviewed-by: Nimrod Oren <noren@nvidia.com>
> Signed-off-by: Gal Pressman <gal@nvidia.com>
> Reviewed-by: Joe Damato <jdamato@fastly.com>

Reviewed-by: Subbaraya Sundeep <sbhatta@marvell.com>

Thanks,
Sundeep

> ---
>  net/ethtool/ioctl.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> index 39ec920f5de7..71c828d0bf31 100644
> --- a/net/ethtool/ioctl.c
> +++ b/net/ethtool/ioctl.c
> @@ -1083,7 +1083,8 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
>  		    ethtool_get_flow_spec_ring(info.fs.ring_cookie))
>  			return -EINVAL;
>  
> -		if (!xa_load(&dev->ethtool->rss_ctx, info.rss_context))
> +		if (info.rss_context &&
> +		    !xa_load(&dev->ethtool->rss_ctx, info.rss_context))
>  			return -EINVAL;
>  	}
>  
> -- 
> 2.40.1
>