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References: <20220630150135.1799535-1-sbinding@opensource.cirrus.com> <20220630150135.1799535-2-sbinding@opensource.cirrus.com>
In-Reply-To: <20220630150135.1799535-2-sbinding@opensource.cirrus.com>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 5 Jul 2022 21:04:59 +0200
Message-ID: <CAHp75VfXwDAwwmzbcx4g1uEuzhzMJ31K1bsTrwYFZGbz3tLMBw@mail.gmail.com>
Subject: Re: [PATCH v5 1/2] ACPI: utils: Add api to read _SUB from ACPI
To:     Stefan Binding <sbinding@opensource.cirrus.com>
Cc:     "Rafael J . Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, Mark Brown <broonie@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        ALSA Development Mailing List <alsa-devel@alsa-project.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        patches@opensource.cirrus.com
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On Thu, Jun 30, 2022 at 5:17 PM Stefan Binding
<sbinding@opensource.cirrus.com> wrote:
>
> Add a wrapper function to read the _SUB string from ACPI.

...

> +       if (obj->type == ACPI_TYPE_STRING) {
> +               if (strlen(obj->string.pointer) < ACPI_MAX_SUB_BUF_SIZE &&
> +                   strlen(obj->string.pointer) > 0) {
> +                       sub = kstrdup(obj->string.pointer, GFP_KERNEL);
> +                       if (!sub)
> +                               sub = ERR_PTR(-ENOMEM);
> +               } else {
> +                       acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n",
> +                                       strlen(obj->string.pointer));

Three times to evaluate strlen()... Can we do better, please?

> +                       sub = ERR_PTR(-EINVAL);
> +               }
> +       } else {
> +               acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
> +               sub = ERR_PTR(-EINVAL);
> +       }

-- 
With Best Regards,
Andy Shevchenko