netdev - Re: net: macb: sparse warning fixes

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Date: Fri, 23 Jun 2023 17:42:33 +0200
From: Nicolas Ferre <nicolas.ferre@...rochip.com>
To: Andrew Lunn <andrew@...n.ch>
CC: Ben Dooks <ben.dooks@...ethink.co.uk>, <netdev@...r.kernel.org>,
	<pabeni@...hat.com>, <kuba@...nel.org>, <edumazet@...gle.com>,
	<davem@...emloft.net>, <linux-kernel@...r.kernel.org>,
	<claudiu.beznea@...rochip.com>
Subject: Re: net: macb: sparse warning fixes

On 23/06/2023 at 17:38, Andrew Lunn wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On Fri, Jun 23, 2023 at 03:16:23PM +0200, Nicolas Ferre wrote:
>> Hi Ben,
>>
>> On 22/06/2023 at 15:05, Ben Dooks wrote:
>>> These are 3 hopefully easy patches for fixing sparse errors due to
>>> endian-ness warnings. There are still some left, but there are not
>>> as easy as they mix host and network fields together.
>>>
>>> For example, gem_prog_cmp_regs() has two u32 variables that it does
>>> bitfield manipulation on for the tcp ports and these are __be16 into
>>> u32, so not sure how these are meant to be changed. I've also no hardware
>>> to test on, so even if these did get changed then I can't check if it is
>>> working pre/post change.
>>
>> Do you know if there could be any impact on performance (even if limited)?
> 
> Hi Nicolas
> 
> This is inside a netdev_dbg(). So 99% of the time it is compiled
> out. The other 1% of the time, your 115200 baud serial port is
> probably the bottleneck, not an endianness swap.

Yeah, sure thing: I was not talking about the 3/3 patch where, yes, 
indeed it doesn't have an importance.

Others in gem_enable_flow_filters() and gem_prog_cmp_regs() look like 
they are away from hot path anyway, so here again probably no impact.

Regards,
   Nicolas

-- 
Nicolas Ferre