Re: [PATCH iwl-next v3 1/6] ip_tunnel: use a separate struct to store tunnel params in the kernel

From: Alexander Lobakin <aleksander.lobakin@intel.com>
To: Andy Shevchenko <andy@kernel.org>
Cc: Marcin Szycik <marcin.szycik@linux.intel.com>,
	<intel-wired-lan@lists.osuosl.org>, <netdev@vger.kernel.org>,
	<wojciech.drewek@intel.com>, <michal.swiatkowski@linux.intel.com>,
	<davem@davemloft.net>, <kuba@kernel.org>, <jiri@resnulli.us>,
	<pabeni@redhat.com>, <jesse.brandeburg@intel.com>,
	<simon.horman@corigine.com>, <idosch@nvidia.com>
Subject: Re: [PATCH iwl-next v3 1/6] ip_tunnel: use a separate struct to store tunnel params in the kernel
Date: Mon, 24 Jul 2023 16:21:52 +0200	[thread overview]
Message-ID: <42a51ef3-9fa7-36e6-77c6-475ad795df3a@intel.com> (raw)
In-Reply-To: <ZLqUfwKkRH85uPlT@smile.fi.intel.com>

From: Andy Shevchenko <andy@kernel.org>
Date: Fri, 21 Jul 2023 17:21:51 +0300

> On Fri, Jul 21, 2023 at 09:15:27AM +0200, Marcin Szycik wrote:
>> From: Alexander Lobakin <aleksander.lobakin@intel.com>
>>
>> Unlike IPv6 tunnels which use purely-kernel __ip6_tnl_parm structure
>> to store params inside the kernel, IPv4 tunnel code uses the same
>> ip_tunnel_parm which is being used to talk with the userspace.
>> This makes it difficult to alter or add any fields or use a
>> different format for whatever data.
>> Define struct ip_tunnel_parm_kern, a 1:1 copy of ip_tunnel_parm for
>> now, and use it throughout the code. The two places where the latter
>> is used to interact with the userspace, now do a conversion from one
>> type to another, with manual field-by-field assignments.
>> Must be done at once, since ip_tunnel::parms is being used in most
>> of those places.
> 
> ...
> 
>> +	strscpy(kp.name, p.name, sizeof(kp.name));
>> +	kp.link = p.link;
>> +	kp.i_flags = p.i_flags;
>> +	kp.o_flags = p.o_flags;
>> +	kp.i_key = p.i_key;
>> +	kp.o_key = p.o_key;
>> +	memcpy(&kp.iph, &p.iph, min(sizeof(kp.iph), sizeof(p.iph)));
>> +
>> +	err = dev->netdev_ops->ndo_tunnel_ctl(dev, &kp, cmd);
>> +	if (err)
>> +		return err;
>> +
>> +	strscpy(p.name, kp.name, sizeof(p.name));
>> +	p.link = kp.link;
>> +	p.i_flags = kp.i_flags;
>> +	p.o_flags = kp.o_flags;
>> +	p.i_key = kp.i_key;
>> +	p.o_key = kp.o_key;
>> +	memcpy(&p.iph, &kp.iph, min(sizeof(p.iph), sizeof(kp.iph)));
> 
>> +		strscpy(kp.name, p.name, sizeof(kp.name));
>> +		kp.link = p.link;
>> +		kp.i_flags = p.i_flags;
>> +		kp.o_flags = p.o_flags;
>> +		kp.i_key = p.i_key;
>> +		kp.o_key = p.o_key;
>> +		memcpy(&kp.iph, &p.iph, min(sizeof(p.iph), sizeof(kp.iph)));
> 
> Seems to me these two deserves separate helpers to avoid such a duplication(s).
> 

Sounds reasonable, thanks!

Olek