Re: [PATCH v4 net-next 2/7] net: ethtool: attach an XArray of custom RSS contexts to a netdevice

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

On 05/10/2023 00:00, Jakub Kicinski wrote:
> On Wed, 27 Sep 2023 19:13:33 +0100 edward.cree@amd.com wrote:
>> +	struct ethtool_rxfh_context *ctx;
>> +	unsigned long context;
>> +
>> +	if (dev->ethtool_ops->set_rxfh_context)
> 
> Can there be contexts if there's no callback to create them?

I don't believe so.  But maybe making that load-bearing isn't great...

> Perhaps you need this for later patches but would be good to
> mention "why" in the commit message.

Well, the loop below tries to call ->set_rxfh_context, which wouldn't
 go too well if there's no callback.  But I guess the code makes more
 sense to read if this just guards the actual call and not the kfree.

-ed

>> +		xa_for_each(&dev->ethtool->rss_ctx, context, ctx) {
>> +			u32 *indir = ethtool_rxfh_context_indir(ctx);
>> +			u8 *key = ethtool_rxfh_context_key(ctx);
>> +			u32 concast = context;
>> +
>> +			xa_erase(&dev->ethtool->rss_ctx, context);
>> +			dev->ethtool_ops->set_rxfh_context(dev, indir, key,
>> +							   ctx->hfunc, &concast,
>> +							   true);
>> +			kfree(ctx);
>> +		}