Re: [patch] gpiolib: fix oops in gpio_get_value_cansleep()

From: Anton Vorontsov
Date: Thu Oct 16 2008 - 12:43:43 EST


On Thu, Oct 16, 2008 at 08:45:22AM -0700, David Brownell wrote:
> From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
[...]
> 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@xxxxxxxxxxxxx>
> Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
> ---
> 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@xxxxxxxxx
irc://irc.freenode.net/bd2
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