linux-kernel - Re: [PATCH] acpi_system_write_wakeup_device(): fix error check for unsigned variable.

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Date:	Thu, 22 Nov 2012 01:23:24 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Cyril Roelandt <tipecaml@...il.com>
Cc:	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	lenb@...nel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] acpi_system_write_wakeup_device(): fix error check for unsigned variable.

On Thursday, November 22, 2012 01:05:30 AM Cyril Roelandt wrote:
> On 11/21/2012 01:44 AM, Rafael J. Wysocki wrote:
> > On Saturday, November 17, 2012 02:54:23 AM Cyril Roelandt wrote:
> >> The LEN variable is unsigned, therefore checking whether it is less than 0 is
> >> useless.
> >>
> >> Signed-off-by: Cyril Roelandt<tipecaml@...il.com>
> >> ---
> >>   drivers/acpi/proc.c |    2 --
> >>   1 file changed, 2 deletions(-)
> >>
> >> diff --git a/drivers/acpi/proc.c b/drivers/acpi/proc.c
> >> index 27adb09..37871a7 100644
> >> --- a/drivers/acpi/proc.c
> >> +++ b/drivers/acpi/proc.c
> >> @@ -366,8 +366,6 @@ acpi_system_write_wakeup_device(struct file *file,
> >>
> >>   	if (len>  4)
> >>   		len = 4;
> >> -	if (len<  0)
> >> -		return -EFAULT;
> >
> > I would prefer to check if count<  0 instead.
> >
> 
> 
> count has type size_t, so it is also an unsigned variable. I think that 
> acpi_system_write_wakeup_device really cannot be called with a "count" 
> parameter that is less than 0.

OK

So I suppose we can just drop len entirely and replace it with count, right?
[And drop the < 0 check too.]

Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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