linux-kernel - Re: [PATCH v2 3/7] test_firmware: add partial read support for request_firmware_into

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Message-ID: <4a666590-461d-17f9-5580-31a41869383f@broadcom.com>
Date:   Fri, 21 Feb 2020 17:13:08 -0800
From:   Scott Branden <scott.branden@...adcom.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     Luis Chamberlain <mcgrof@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        David Brown <david.brown@...aro.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Shuah Khan <shuah@...nel.org>, bjorn.andersson@...aro.org,
        Shuah Khan <skhan@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-fsdevel@...r.kernel.org,
        BCM Kernel Feedback <bcm-kernel-feedback-list@...adcom.com>,
        Olof Johansson <olof@...om.net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Colin Ian King <colin.king@...onical.com>,
        Kees Cook <keescook@...omium.org>,
        Takashi Iwai <tiwai@...e.de>, linux-kselftest@...r.kernel.org,
        Andy Gross <agross@...nel.org>
Subject: Re: [PATCH v2 3/7] test_firmware: add partial read support for
 request_firmware_into_buf

Reponses inline.

Luis - please have a look as well.

On 2020-02-21 10:30 a.m., Scott Branden wrote:
> Hi Dan,
>
> Thanks for your review and valuable comments.
> Will have to investigate fully and correct anything wrong.
>
> On 2020-02-20 12:42 a.m., Dan Carpenter wrote:
>> On Wed, Feb 19, 2020 at 04:48:21PM -0800, Scott Branden wrote:
>>> +static int test_dev_config_update_size_t(const char *buf,
>>> +                     size_t size,
>>> +                     size_t *cfg)
>>> +{
>>> +    int ret;
>>> +    long new;
>>> +
>>> +    ret = kstrtol(buf, 10, &new);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    if (new > SIZE_MAX)
>> This "new" variable is long and SIZE_MAX is ULONG_MAX so the condition
>> can't be true.
Removed the check.
>>
>>> +        return -EINVAL;
>>> +
>>> +    mutex_lock(&test_fw_mutex);
>>> +    *(size_t *)cfg = new;
>>> +    mutex_unlock(&test_fw_mutex);
>>> +
>>> +    /* Always return full write size even if we didn't consume all */
>>> +    return size;
>>> +}
>>> +
>>> +static ssize_t test_dev_config_show_size_t(char *buf, int cfg)
>>> +{
>>> +    size_t val;
>>> +
>>> +    mutex_lock(&test_fw_mutex);
>>> +    val = cfg;
>>> +    mutex_unlock(&test_fw_mutex);
>> Both val and cfg are stack variables so there is no need for locking.
>> Probably you meant to pass a pointer to cfg?
I am following the existing code as was done for
test_dev_config_show_bool(),
test_dev_config_show_int(),
test_dev_config_show_u8()

Mutex probably not needed but I don't think I need to deviate from the 
rest of the test code.

Luis, could you please explain what the rest of your code is doing?
>>
>>> +
>>> +    return snprintf(buf, PAGE_SIZE, "%zu\n", val);
>>> +}
>>> +
>>>   static ssize_t test_dev_config_show_int(char *buf, int cfg)
>>>   {
>>>       int val;
>> regards,
>> dan carpenter
>>
>>
>