linux-kernel - Re: [rtc-linux] [PATCH 2/2] rtc: mediatek: Add MT63xx RTC driver

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

Message-ID: <20150313105742.GS24885@pengutronix.de>
Date:	Fri, 13 Mar 2015 11:57:42 +0100
From:	Sascha Hauer <s.hauer@...gutronix.de>
To:	Eddie Huang <eddie.huang@...iatek.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Mark Rutland <mark.rutland@....com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	srv_heupstream@...iatek.com, Pawel Moll <pawel.moll@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	rtc-linux@...glegroups.com, yh.chen@...iatek.com,
	linux-kernel@...r.kernel.org,
	Tianping Fang <tianping.fang@...iatek.com>,
	Grant Likely <grant.likely@...aro.org>,
	devicetree@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
	linux-mediatek@...ts.infradead.org,
	Sascha Hauer <kernel@...gutronix.de>,
	Kumar Gala <galak@...eaurora.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	yingjoe.chen@...iatek.com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [rtc-linux] [PATCH 2/2] rtc: mediatek: Add MT63xx RTC driver

Hi Eddie,

On Fri, Mar 13, 2015 at 06:29:23PM +0800, Eddie Huang wrote:
> > regmap_read() and regmap_write() can return errors.  There is no
> > checking for this.
> > 
> 
> I encounter some trouble when I add code to check return value of
> regmap_read and regmap_write. Every RTC register access through regmap,
> and there are many register read/write in this driver. If I check every
> return value, the driver will become ugly. I try to make this driver
> clean using following macro.
> 
> static int __rtc_read(struct mt6397_rtc *rtc, u32 offset, u32 *data)
> {
>         u32 addr = rtc->addr_base + offset;
> 
>         if (offset < rtc->addr_range)
>                 return regmap_read(rtc->regmap, addr, data);
> 
>         return -EINVAL;
> }
> 
> #define rtc_read(ret, rtc, offset, data)                \
> ({                                                      \
>         ret = __rtc_read(rtc, offset, data);            \
>         if (ret < 0)                                    \
>                 goto rtc_exit;                          \
> })                                                      \

Hiding a goto (or return) in a macro is a very bad idea.

what you can do is

	ret |= regmap_read(rtc->regmap, RTC_TC_SEC, &tm->tm_sec);
	ret |= regmap_read(rtc->regmap, RTC_TC_MIN, &tm->tm_min);

	if (ret)
		return -EIO;

(Don't return ret in this case though as it might contain different
error codes orred together)

Another possibilty at least for contiguous registers would be
regmap_bulk_read().

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
--
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/