linux-kernel - Re: [patch] gpiolib: fix oops in gpio_get_value

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Date:	Thu, 16 Oct 2008 20:43:30 +0400
From:	Anton Vorontsov <avorontsov@...mvista.com>
To:	David Brownell <david-b@...bell.net>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [patch] gpiolib: fix oops in gpio_get_value_cansleep()

On Thu, Oct 16, 2008 at 08:45:22AM -0700, David Brownell wrote:
> From: David Brownell <dbrownell@...rs.sourceforge.net>
[...]
> So the problem is that gpio_get_value_cansleep() isn't making
> the same sanity check that gpio_get_value() does:  making sure
> this GPIO isn't one of the atypical "no input logic" cases.
> 
> Reported-by: Anton Vorontsov <avorontsov@...mvista.com>
> Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
> ---
>  drivers/gpio/gpiolib.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1056,7 +1056,7 @@ int gpio_get_value_cansleep(unsigned gpi
>  
>  	might_sleep_if(extra_checks);
>  	chip = gpio_to_chip(gpio);
> -	return chip->get(chip, gpio - chip->base);
> +	return chip->get ? chip->get(chip, gpio - chip->base) : 0;

Why don't we check the .set in the gpio_set_value? Because
we must always call gpio_direction_output()? It is not exactly the
same we work with the input direction.. is this documented anywhere?

-- 
Anton Vorontsov
email: cbouatmailru@...il.com
irc://irc.freenode.net/bd2
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