Re: [PATCH ethtool-next v2] rxclass: Make output for RSS context action explicit

[Edward Cree <ecree.xilinx@gmail.com>]

On 11/11/2024 19:05, Daniel Xu wrote:
> Currently `ethtool -n` prints out misleading output if the action for an
> ntuple rule is to redirect to an RSS context. For example:
> 
>     # ethtool -X eth0 hfunc toeplitz context new start 24 equal 8
>     New RSS context is 1
> 
>     # ethtool -N eth0 flow-type ip6 dst-ip $IP6 context 1
>     Added rule with ID 0
> 
>     # ethtool -n eth0 rule 0
>     Filter: 0
>             Rule Type: Raw IPv6
>             Src IP addr: :: mask: ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
>             Dest IP addr: <redacted> mask: ::
>             Traffic Class: 0x0 mask: 0xff
>             Protocol: 0 mask: 0xff
>             L4 bytes: 0x0 mask: 0xffffffff
>             RSS Context ID: 1
>             Action: Direct to queue 0
> 
> The above output suggests that the HW will direct to queue 0 where in
> reality queue 0 is just the base offset from which the redirection table
> lookup in the RSS context is added to.
> 
> Fix by making output more clear. Also suppress base offset queue for the
> common case of 0. Example of new output:
> 
>     # ./ethtool -n eth0 rule 0
>     Filter: 0
>             Rule Type: Raw IPv6
>             Src IP addr: :: mask: ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
>             Dest IP addr: <redacted> mask: ::
>             Traffic Class: 0x0 mask: 0xff
>             Protocol: 0 mask: 0xff
>             L4 bytes: 0x0 mask: 0xffffffff
>             Action: Direct to RSS context id 1
> 
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>

Reviewed-by: Edward Cree <ecree.xilinx@gmail.com>

but someone who understands ethtool_get_flow_spec_ring_vf() should
 look at this as well to check whether that information's needed too.

> ---
> Changes from v1:
> * Reword to support queue base offset API
> * Fix compile error
> * Improve wording (also a transcription error)
> 
>  rxclass.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/rxclass.c b/rxclass.c
> index f17e3a5..ac9b529 100644
> --- a/rxclass.c
> +++ b/rxclass.c
> @@ -248,13 +248,17 @@ static void rxclass_print_nfc_rule(struct ethtool_rx_flow_spec *fsp,
>  
>  	rxclass_print_nfc_spec_ext(fsp);
>  
> -	if (fsp->flow_type & FLOW_RSS)
> -		fprintf(stdout, "\tRSS Context ID: %u\n", rss_context);
> -
>  	if (fsp->ring_cookie == RX_CLS_FLOW_DISC) {
>  		fprintf(stdout, "\tAction: Drop\n");
>  	} else if (fsp->ring_cookie == RX_CLS_FLOW_WAKE) {
>  		fprintf(stdout, "\tAction: Wake-on-LAN\n");
> +	} else if (fsp->flow_type & FLOW_RSS) {
> +		u64 queue = ethtool_get_flow_spec_ring(fsp->ring_cookie);
> +
> +		fprintf(stdout, "\tAction: Direct to RSS context id %u", rss_context);
> +		if (queue)
> +			fprintf(stdout, " (queue base offset: %llu)", queue);
> +		fprintf(stdout, "\n");
>  	} else {
>  		u64 vf = ethtool_get_flow_spec_ring_vf(fsp->ring_cookie);
>  		u64 queue = ethtool_get_flow_spec_ring(fsp->ring_cookie);
>