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Message-ID: <2375c9f90703140700k9fb4606pad0f0dc401764323@mail.gmail.com>
Date: Wed, 14 Mar 2007 22:00:44 +0800
From: "Cong WANG" <xiyou.wangcong@gmail.com>
To: linux-kernel@vger.kernel.org, "Nicolas Boichat" <nicolas@boichat.ch>
Subject: Re: [RFC][PATCH] Apple SMC driver (hardware monitoring and control)
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2007/3/14, Cong WANG wrote:
> I am sorry. I forgot to CC to the list.
>
> 2007/3/14, Nicolas Boichat wrote:
> > Hello,
> >
>
> <snip>
>
> > +static ssize_t applesmc_show_fan_manual(struct device *dev, char *buf,
> > +                                                               int offset)
> > +{
> > +       int ret;
> > +       u16 manual = 0;
> > +       u8 buffer[2];
> > +
> > +       down(&applesmc_sem);
> > +
> > +       ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
> > +       manual = ((buffer[0] << 8 | buffer[1]) >> offset) & 0x01;
> > +
> > +       up(&applesmc_sem);
> > +       if (ret)
> > +               return ret;
> > +       else
> > +               return sprintf(buf, "%d\n", manual);
> > +}
> > +
>
> I doubt about your last 'sprintf'. Your 'buf' just has only two 'u8's,
> which maybe only has two bytes, and '\n' already consumes one. So only
> one byte is left for the decimal vaule of 'manual'. Even it is just
> less than 10, just as what you want, the final '\0' is omitted!
>
> What's more, you can't get such information from the return value of
> 'sprintf'. So I suggest you to choose 'snprintf' instead.
>

Sorry. I thought his 'buffer' as 'buf'. But my suggestion is still
worthy your thinking.