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  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 24 Jul 2014 06:16:40 +0200
From:	Marek Vasut <marex@...x.de>
To:	Yao Yuan <yao.yuan@...escale.com>
Cc:	"wsa@...-dreams.de" <wsa@...-dreams.de>,
	"mark.rutland@....com" <mark.rutland@....com>,
	"shawn.guo@...aro.org" <shawn.guo@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>
Subject: Re: [PATCH v5 0/2] i2c: add DMA support for freescale i2c driver

On Thursday, July 24, 2014 at 05:36:34 AM, Yao Yuan wrote:
> Hi,
> 
> Marek Vasut wrote:
> > On Wednesday, July 23, 2014 at 10:24:41 AM, Yuan Yao wrote:
> > > Changed in v5:
> > > - add "*chan_dev = dma->chan_using->device->dev" for reduce the call
> > > time.
> > 
> > Did you check if the compiler generates different code ?
> 
> Sorry, I didn't compare the assembly code. It's a subtle change.
> As you mentioned the "noodle" before.
> 
> Old:
> dma_map_single(dma->chan_using->device->dev, ...);
> dma_mapping_error(dma->chan_using->device->dev, ...);
> dma_unmap_single(dma->chan_using->device->dev, ...);
> 
> New:
> struct device *chan_dev = dma->chan_using->device->dev;
> dma_map_single(chan_dev, ...);
> dma_mapping_error(chan_dev, ...);
> dma_unmap_single(chan_dev, ...);

You should not use optimization and code cleanup interchangably. Thanks for 
clarifying what this is.

Best regards,
Marek Vasut
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists