linux-kernel - Re: [PATCH v3 16/22] ACPI: platform_profile: Set profile for all registered handlers

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Message-ID: <362d8939-20ed-40c2-95b4-f687dc20f6cc@amd.com>
Date: Thu, 31 Oct 2024 08:18:06 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Hans de Goede <hdegoede@...hat.com>,
 "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
 Maximilian Luz <luzmaximilian@...il.com>, Lee Chun-Yi <jlee@...e.com>,
 Shyam Sundar S K <Shyam-sundar.S-k@....com>,
 Corentin Chary <corentin.chary@...il.com>, "Luke D . Jones"
 <luke@...nes.dev>, Ike Panhc <ike.pan@...onical.com>,
 Henrique de Moraes Holschuh <hmh@....eng.br>,
 Alexis Belmonte <alexbelm48@...il.com>,
 Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
 Ai Chao <aichao@...inos.cn>, Gergo Koteles <soyer@....hu>,
 open list <linux-kernel@...r.kernel.org>,
 "open list:ACPI" <linux-acpi@...r.kernel.org>,
 "open list:MICROSOFT SURFACE PLATFORM PROFILE DRIVER"
 <platform-driver-x86@...r.kernel.org>,
 "open list:THINKPAD ACPI EXTRAS DRIVER"
 <ibm-acpi-devel@...ts.sourceforge.net>,
 Mark Pearson <mpearson-lenovo@...ebb.ca>,
 Matthew Schwartz <matthew.schwartz@...ux.dev>
Subject: Re: [PATCH v3 16/22] ACPI: platform_profile: Set profile for all
 registered handlers

On 10/31/2024 05:25, Ilpo Järvinen wrote:
> On Wed, 30 Oct 2024, Mario Limonciello wrote:
> 
>> If multiple platform profile handlers have been registered then when
>> setting a profile verify that all profile handlers support the requested
>> profile and set it to each handler.
>>
>> If this fails for any given handler, revert all profile handlers back to
>> balanced and log an error into the kernel ring buffer.
>>
>> Tested-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>> ---
>>   drivers/acpi/platform_profile.c | 25 ++++++++++++++++++++-----
>>   1 file changed, 20 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
>> index 90cbc0de4d5bc..c2bb325ba531c 100644
>> --- a/drivers/acpi/platform_profile.c
>> +++ b/drivers/acpi/platform_profile.c
>> @@ -99,6 +99,8 @@ static ssize_t platform_profile_store(struct device *dev,
>>   			    struct device_attribute *attr,
>>   			    const char *buf, size_t count)
>>   {
>> +	struct platform_profile_handler *handler;
>> +	unsigned long choices;
>>   	int err, i;
>>   
>>   	/* Scan for a matching profile */
>> @@ -107,16 +109,29 @@ static ssize_t platform_profile_store(struct device *dev,
>>   		return -EINVAL;
>>   
>>   	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
>> -		if (!cur_profile)
>> +		if (!platform_profile_is_registered())
>>   			return -ENODEV;
>>   
>> -		/* Check that platform supports this profile choice */
>> -		if (!test_bit(i, cur_profile->choices))
>> +		/* Check that all handlers support this profile choice */
>> +		choices = platform_profile_get_choices();
>> +		if (!test_bit(i, &choices))
>>   			return -EOPNOTSUPP;
>>   
>> -		err = cur_profile->profile_set(cur_profile, i);
>> -		if (err)
>> +		list_for_each_entry(handler, &platform_profile_handler_list, list) {
>> +			err = handler->profile_set(handler, i);
>> +			if (err) {
>> +				pr_err("Failed to set profile for handler %s\n", handler->name);
>> +				break;
>> +			}
>> +		}
>> +		if (err) {
>> +			list_for_each_entry_continue_reverse(handler, &platform_profile_handler_list, list) {
> 
> Too long line.
> 
> This looks an error rollback though so instead of break inside the loop
> you could goto into a label at the end of the function and have much less
> indentation to begin with.

How does the scoped_cond_guard interact with a goto?  With the jump I 
had guessed it goes out of scope, but I wasn't really sure what the 
compiler does.

I guess in the goto label I'll need another scoped_cond_guard()?

> 
>> +				if (handler->profile_set(handler, PLATFORM_PROFILE_BALANCED))
>> +					pr_err("Failed to revert profile for handler %s\n",
>> +					       handler->name);
>> +			}
>>   			return err;
>> +		}
>>   	}
>>   
>>   	sysfs_notify(acpi_kobj, NULL, "platform_profile");
>>
>