Re: [PATCH v4] gpio: sim: fix an invalid __free() usage

Andy Shevchenko
2023-09-18T15:42:29Z

On Mon, Sep 18, 2023 at 04:55:33PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> gpio_sim_make_line_names() returns NULL or ERR_PTR() so we must not use
> __free(kfree) on the returned address. Split this function into two, one
> that determines the size of the "gpio-line-names" array to allocate and
> one that actually sets the names at correct offsets. The allocation and
> assignment of the managed pointer happens in between.

...

> + unsigned int size = 0;
>
> list_for_each_entry(line, &bank->line_list, siblings) {
> + if (!line->name || (line->offset >= bank->num_lines))
> continue;
>
> + size = line->offset + 1;
> }
>
> + return size;

So, now the function iterates over all lines and returns the size of the last
match, correct?

Why not

list_for_each_entry_reversed() {
if (line->name && ())
break;
}

return size;

?

...

> +static void
> +gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
> +{
> + struct gpio_sim_line *line;
>
> list_for_each_entry(line, &bank->line_list, siblings) {
> - if (line->offset >= bank->num_lines)
> + if (!line->name || (line->offset >= bank->num_lines))
> continue;
>
> - if (line->name && (line->offset <= max_offset))
> - line_names[line->offset] = line->name;
> + line_names[line->offset] = line->name;
> }
> -
> - return line_names;
> }

Can be done in the similar (I see the difference) way for the consistency with
above.

...

> + line_names_size = gpio_sim_get_line_names_size(bank);

> + if (line_names_size) {

Of course this can be replace with...

> + line_names = kcalloc(line_names_size, sizeof(*line_names),
> + GFP_KERNEL);

> + if (!line_names)

ZERO_OR_NULL_PTR() check here, but I assume we discourage use of it.

> + return ERR_PTR(-ENOMEM);
> +
> + gpio_sim_set_line_names(bank, line_names);
>
> - if (line_names)
> properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
> "gpio-line-names",
> line_names, line_names_size);
> + }

--
With Best Regards,
Andy Shevchenko