linux-kernel - Re: [PATCH v4 2/2] pinctrl: pinmux: Add pinmux-select debugfs file

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Date:   Thu, 11 Feb 2021 10:11:53 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Drew Fustini <drew@...gleboard.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tony Lindgren <tony@...mide.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Jason Kridner <jkridner@...gleboard.org>,
        Robert Nelson <robertcnelson@...gleboard.org>,
        Joe Perches <joe@...ches.com>
Subject: Re: [PATCH v4 2/2] pinctrl: pinmux: Add pinmux-select debugfs file

On Wed, Feb 10, 2021 at 02:28:54PM -0800, Drew Fustini wrote:
> +	ret = strncpy_from_user(buf, user_buf, PINMUX_MAX_NAME * 2);
> +	if (ret < 0) {
> +		dev_err(pctldev->dev, "failed to copy buffer from userspace");
> +		goto free_gname;
> +	}
> +	buf[len-1] = '\0';
> +
> +	ret = sscanf(buf, "%s %s", fname, gname);
> +	if (ret != 2) {
> +		dev_err(pctldev->dev, "expected format: <function-name> <group-name>");
> +		goto free_gname;

We need a "ret = -EINVAL;" before the goto.  sscanf doesn't return error
codes.  Normally we would write it like so:

	if (sscanf(buf, "%s %s", fname, gname) != 2) {
		dev_err(pctldev->dev, "expected format: <function-name> <group-name>");
		ret = -EINVAL;
		goto free_gname;
	}

I'm going to write a Smatch check for this today.

> +	}
> +
> +	fsel = pinmux_func_name_to_selector(pctldev, fname);
> +	if (fsel < 0) {
> +		dev_err(pctldev->dev, "invalid function %s in map table\n", fname);
> +		ret = -EINVAL;

ret = fsel;

> +		goto free_gname;
> +	}
> +

regards,
dan carpenter