linux-kernel - Re: [PATCH] soundwire: bus_type: fix remove and shutdown support

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Message-ID: <a861f3b2-dec4-982d-0939-1dfc18dd2f53@linux.intel.com>
Date:   Thu, 23 Jun 2022 09:54:36 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Vinod Koul <vkoul@...nel.org>,
        Bard Liao <yung-chuan.liao@...ux.intel.com>
Cc:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        gregkh@...uxfoundation.org, srinivas.kandagatla@...aro.org,
        sanyog.r.kale@...el.com, bard.liao@...el.com
Subject: Re: [PATCH] soundwire: bus_type: fix remove and shutdown support



On 6/23/22 02:55, Vinod Koul wrote:
> On 10-06-22, 09:51, Bard Liao wrote:
>> From: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
>>
>> The bus sdw_drv_remove() and sdw_drv_shutdown() helpers are used
>> conditionally, if the driver provides these routines.
>>
>> These helpers already test if the driver provides a .remove or
>> .shutdown callback, so there's no harm in invoking the
>> sdw_drv_remove() and sdw_drv_shutdown() unconditionally.
> 
> Okay sounds good
> 
>> In addition, the current code is imbalanced with
>> dev_pm_domain_attach() called from sdw_drv_probe(), but
>> dev_pm_domain_detach() called from sdw_drv_remove() only if the driver
>> provides a .remove callback.
> 
> Am not sure I follow what is imbalance, pm_domain_attach/detach?

Yes, the dev_pm_domain_detach() is done conditionally, depending on the
presence of a driver .remove callback, that's not so good.

>> Fixes: 9251345dca24b ("soundwire: Add SoundWire bus type")
> 
> How is this a fix is still unclear to me. At best I think this is code
> optimization and removing checks which maybe redundant.

I think the Fixes tag is appropriate for the dev_pm_domain_detach()
problem, but if you want to drop it that's fine with me.


>> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
>> Reviewed-by: Rander Wang <rander.wang@...el.com>
>> Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
>> ---
>>  drivers/soundwire/bus_type.c | 8 ++------
>>  1 file changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
>> index 893296f3fe39..b81e04dd3a9f 100644
>> --- a/drivers/soundwire/bus_type.c
>> +++ b/drivers/soundwire/bus_type.c
>> @@ -193,12 +193,8 @@ int __sdw_register_driver(struct sdw_driver *drv, struct module *owner)
>>  
>>  	drv->driver.owner = owner;
>>  	drv->driver.probe = sdw_drv_probe;
>> -
>> -	if (drv->remove)
>> -		drv->driver.remove = sdw_drv_remove;
>> -
>> -	if (drv->shutdown)
>> -		drv->driver.shutdown = sdw_drv_shutdown;
>> +	drv->driver.remove = sdw_drv_remove;
>> +	drv->driver.shutdown = sdw_drv_shutdown;
>>  
>>  	return driver_register(&drv->driver);
>>  }
>> -- 
>> 2.17.1
>