linux-kernel - Re: [PATCH v6 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES

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Date:   Thu, 3 Sep 2020 09:59:17 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Kent Gibson <warthog618@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v6 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL

On Mon, Aug 31, 2020 at 5:23 AM Kent Gibson <warthog618@...il.com> wrote:
>
> Add support for the GPIO_V2_LINE_SET_VALUES_IOCTL.
>
> Signed-off-by: Kent Gibson <warthog618@...il.com>
> ---
>  drivers/gpio/gpiolib-cdev.c | 59 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
>
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index 936b8c9958dd..9f05bbd2161e 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -777,6 +777,63 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
>         return 0;
>  }
>
> +static long linereq_set_values_unlocked(struct linereq *lr,
> +                                       struct gpio_v2_line_values *lv)
> +{
> +       DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
> +       struct gpio_desc **descs;
> +       unsigned int i, didx, num_set;
> +       int ret;
> +
> +       bitmap_zero(vals, GPIO_V2_LINES_MAX);
> +       for (num_set = 0, i = 0; i < lr->num_lines; i++) {
> +               if (lv->mask & BIT_ULL(i)) {
> +                       if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
> +                               return -EPERM;
> +                       if (lv->bits & BIT_ULL(i))
> +                               __set_bit(num_set, vals);
> +                       num_set++;
> +                       descs = &lr->lines[i].desc;
> +               }
> +       }
> +       if (num_set == 0)
> +               return -EINVAL;
> +
> +       if (num_set != 1) {
> +               /* build compacted desc array and values */
> +               descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);

Missing retval check.

> +               for (didx = 0, i = 0; i < lr->num_lines; i++) {
> +                       if (lv->mask & BIT_ULL(i)) {
> +                               descs[didx] = lr->lines[i].desc;
> +                               didx++;
> +                       }
> +               }
> +       }
> +       ret = gpiod_set_array_value_complex(false, true, num_set,
> +                                           descs, NULL, vals);
> +
> +       if (num_set != 1)
> +               kfree(descs);
> +       return ret;
> +}
> +
> +static long linereq_set_values(struct linereq *lr, void __user *ip)
> +{
> +       struct gpio_v2_line_values lv;
> +       int ret;
> +
> +       if (copy_from_user(&lv, ip, sizeof(lv)))
> +               return -EFAULT;
> +
> +       mutex_lock(&lr->config_mutex);
> +
> +       ret = linereq_set_values_unlocked(lr, &lv);
> +
> +       mutex_unlock(&lr->config_mutex);
> +
> +       return ret;
> +}
> +
>  static long linereq_set_config_unlocked(struct linereq *lr,
>                                         struct gpio_v2_line_config *lc)
>  {
> @@ -853,6 +910,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd,
>
>         if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
>                 return linereq_get_values(lr, ip);
> +       else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
> +               return linereq_set_values(lr, ip);
>         else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
>                 return linereq_set_config(lr, ip);
>
> --
> 2.28.0
>