Re: [PATCH v4 16/20] ACPI: platform_profile: Make sure all profile handlers agree on profile

[Mario Limonciello <mario.limonciello@amd.com>]

On 11/6/2024 14:58, Armin Wolf wrote:
> Am 05.11.24 um 16:33 schrieb Mario Limonciello:
> 
>> If for any reason multiple profile handlers don't agree on the profile
>> return the custom profile.
>>
>> Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> ---
>>   drivers/acpi/platform_profile.c | 84 +++++++++++++++++++++------------
>>   1 file changed, 53 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/ 
>> platform_profile.c
>> index d8c2d195106c2..7861fccc2e58c 100644
>> --- a/drivers/acpi/platform_profile.c
>> +++ b/drivers/acpi/platform_profile.c
>> @@ -280,55 +280,77 @@ static ssize_t 
>> platform_profile_choices_show(struct device *dev,
>>       return _commmon_choices_show(aggregate, buf);
>>   }
>>
>> -static ssize_t platform_profile_show(struct device *dev,
>> -                    struct device_attribute *attr,
>> -                    char *buf)
>> +/**
>> + * _aggregate_profiles - Aggregate the profiles for legacy sysfs 
>> interface
>> + * @dev: The device
>> + * @data: The profile to return
>> + * Return: 0 on success, -errno on failure
>> + */
>> +static int _aggregate_profiles(struct device *dev, void *data)
>>   {
>> -    enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
>> +    enum platform_profile_option *profile = data;
>> +    enum platform_profile_option val;
>>       int err;
>>
>> -    scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
>> -        if (!cur_profile)
>> -            return -ENODEV;
>> +    err = get_class_profile(dev, &val);
>> +    if (err)
>> +        return err;
>>
>> -        err = cur_profile->profile_get(cur_profile, &profile);
>> -        if (err)
>> -            return err;
>> -    }
>> +    if (*profile != PLATFORM_PROFILE_LAST && *profile != val)
>> +        *profile = PLATFORM_PROFILE_CUSTOM;
>> +    else
>> +        *profile = val;
>>
>> -    /* Check that profile is valid index */
>> -    if (WARN_ON((profile < 0) || (profile >= 
>> ARRAY_SIZE(profile_names))))
>> -        return -EIO;
> 
> Please check the returned value from profile_get() first before doing
> the custom platform
> profile check.

You might have missed it - that's part of get_class_profile() already.

> 
>> +    return 0;
>> +}
>> +
>> +/**
>> + * platform_profile_show - Show the current profile for legacy sysfs 
>> interface
>> + * @dev: The device
>> + * @attr: The attribute
>> + * @buf: The buffer to write to
>> + * Return: The number of bytes written
>> + */
>> +static ssize_t platform_profile_show(struct device *dev,
>> +                     struct device_attribute *attr,
>> +                     char *buf)
>> +{
>> +    enum platform_profile_option profile = PLATFORM_PROFILE_LAST;
>> +    int err;
>> +
>> +    err = class_for_each_device(&platform_profile_class, NULL,
>> +                    &profile, _aggregate_profiles);
> 
> Missing error handling.
> 

Right, got it.

>>
>>       return sysfs_emit(buf, "%s\n", profile_names[profile]);
>>   }
>>
>> +/**
>> + * platform_profile_store - Set the profile for legacy sysfs interface
>> + * @dev: The device
>> + * @attr: The attribute
>> + * @buf: The buffer to read from
>> + * @count: The number of bytes to read
>> + * Return: The number of bytes read
>> + */
>>   static ssize_t platform_profile_store(struct device *dev,
>> -                struct device_attribute *attr,
>> -                const char *buf, size_t count)
>> +                      struct device_attribute *attr,
>> +                      const char *buf, size_t count)
>>   {
>> -    int err, i;
>> +    int ret;
>> +    int i;
>>
>>       /* Scan for a matching profile */
>>       i = sysfs_match_string(profile_names, buf);
>>       if (i < 0)
>>           return -EINVAL;
>> -
>> -    scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
>> -        if (!cur_profile)
>> -            return -ENODEV;
>> -
>> -        /* Check that platform supports this profile choice */
>> -        if (!test_bit(i, cur_profile->choices))
>> -            return -EOPNOTSUPP;
>> -
>> -        err = cur_profile->profile_set(cur_profile, i);
>> -        if (err)
>> -            return err;
>> +    if (i == PLATFORM_PROFILE_CUSTOM) {
>> +        pr_warn("Custom profile not supported for legacy sysfs 
>> interface\n");
> 
> This would allow userspace applications to spam the kernel log. Please
> just return -EINVAL here
> and document this special case inside the interface specification.
> 
OK.

> Thanks,
> Armin Wolf
> 
>> +        return -EINVAL;
>>       }
>>
>> -    sysfs_notify(acpi_kobj, NULL, "platform_profile");
>> -    return count;
>> +    ret = class_for_each_device(&platform_profile_class, NULL, &i, 
>> _store_class_profile);
>> +
>> +    return ret ? ret : count;
>>   }
>>
>>   static DEVICE_ATTR_RO(platform_profile_choices);