netdev - Re: [PATCH V2 01/14] clk: add helper functions clk_prepare_enable and clk_disable_unprepare

Open Source and information security mailing list archives

Date:	Fri, 11 Nov 2011 17:05:47 +0800
From:	Richard Zhao <richard.zhao@...aro.org>
To:	Sascha Hauer <s.hauer@...gutronix.de>
CC:	<amit.kucheria@...onical.com>, <linux@....linux.org.uk>,
	<kernel@...gutronix.de>, <netdev@...r.kernel.org>,
	<linux-mmc@...r.kernel.org>, <ben-linux@...ff.org>,
	<eric.miao@...aro.org>, <linux-i2c@...r.kernel.org>,
	<linux-serial@...r.kernel.org>, <cjb@...top.org>,
	<linux-arm-kernel@...ts.infradead.org>, <alan@...ux.intel.com>
Subject: Re: [PATCH V2 01/14] clk: add helper functions clk_prepare_enable
 and clk_disable_unprepare

On Fri, Nov 11, 2011 at 09:49:50AM +0100, Sascha Hauer wrote:
> On Fri, Nov 11, 2011 at 09:10:16AM +0800, Richard Zhao wrote:
> > Signed-off-by: Richard Zhao <richard.zhao@...aro.org>
> > ---
> >  include/linux/clk.h |   19 +++++++++++++++++++
> >  1 files changed, 19 insertions(+), 0 deletions(-)
> > 
> > diff --git a/include/linux/clk.h b/include/linux/clk.h
> > index 7213b52..63985f7 100644
> > --- a/include/linux/clk.h
> > +++ b/include/linux/clk.h
> > @@ -107,6 +107,25 @@ static inline void clk_unprepare(struct clk *clk)
> >  }
> >  #endif
> >  
> > +static inline int clk_prepare_enable(struct clk *clk)
> > +{
> > +	int ret;
> > +
> > +	ret = clk_prepare(clk);
> > +	if (!ret)
> > +		ret = clk_enable(clk);
> > +	if (ret)
> > +		clk_unprepare(clk);
> 
> As Baruch already pointed out this is hard to read. Also it contains a
> bug. When clk_prepare fails clk_unprepare is called afterwards.
> 
> Hint: Kernel guys are not afraid of having multiple return statements
> in a function, instead they like it when something is handled early
> without having to read the rest of the function.
{
	int ret;

	ret = clk_prepare(clk);
	if (ret)
		return ret;
	ret = clk_enable(clk);
	if (ret)
		clk_unprepare(clk);
	return ret;

Like above code? Thanks for review.

Richard
> 
> 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 |
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

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