linux-kernel - Re: [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling variables

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20160705150121.GF1257@jack.zhora.eu>
Date:	Wed, 6 Jul 2016 00:01:21 +0900
From:	Andi Shyti <andi@...zian.org>
To:	Mark Brown <broonie@...nel.org>
Cc:	Andi Shyti <andi.shyti@...sung.com>, Kukjin Kim <kgene@...nel.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Jaehoon Chung <jh80.chung@...sung.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-spi@...r.kernel.org,
	linux-kernel@...r.kernel.org, Andi Shyti <andi@...zian.org>
Subject: Re: [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling
 variables

Hi Mark,

> > The 'quirks' variable cannot ever be negative, therefore use u8
> > instead of int. The 8 bit size is given from the fact that
> > currently the quirks variable has very few statuses.
> > 
> > The rx_lvl_offset and tx_st_done store shift values, so that u8
> > is a proper size.
> > 
> > fifo_lvl_mask stores a series of masks, to be in we will keep the
> > 32 bit size.
> 
> What's the advantage of these changes?  This feels like microptimisation
> of something that shouldn't be a big performance issue and it's not
> always the case that the compiler does something more sensible with
> smaller or unsigned types.  I'm not saying don't do it, I'm just saying
> that it's not clear to me what the win is.

not much indeed. Just something that was a little bothering me
while I was reading through.

Please, feel free to drop it.

Thanks,
Andi