Re: [PATCH v2 2/2] driver core: add helper for deferred probe reason setting

[Ahmad Fatoum]

Hello,

On 23.03.21 15:07, Greg Kroah-Hartman wrote:
> On Fri, Mar 19, 2021 at 12:04:58PM +0100, Ahmad Fatoum wrote:
>> We now have three places within the same file doing the same operation
>> of freeing this pointer and setting it anew. A helper make this
>> arguably easier to read, so add one.
>>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
>> ---
>> v1 -> v2:
>>  - no change
>> ---
>>  drivers/base/dd.c | 17 +++++++++++------
>>  1 file changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
>> index e2cf3b29123e..4201baa1cc13 100644
>> --- a/drivers/base/dd.c
>> +++ b/drivers/base/dd.c
>> @@ -69,6 +69,12 @@ static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
>>   */
>>  static bool defer_all_probes;
>>  
>> +static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
>> +{
>> +	kfree(dev->p->deferred_probe_reason);
>> +	dev->p->deferred_probe_reason = reason;
>> +}
>> +
>>  /*
>>   * deferred_probe_work_func() - Retry probing devices in the active list.
>>   */
>> @@ -97,8 +103,7 @@ static void deferred_probe_work_func(struct work_struct *work)
>>  
>>  		get_device(dev);
>>  
>> -		kfree(dev->p->deferred_probe_reason);
>> -		dev->p->deferred_probe_reason = NULL;
>> +		__device_set_deferred_probe_reason(dev, NULL);
>>  
>>  		/*
>>  		 * Drop the mutex while probing each device; the probe path may
>> @@ -140,8 +145,7 @@ void driver_deferred_probe_del(struct device *dev)
>>  	if (!list_empty(&dev->p->deferred_probe)) {
>>  		dev_dbg(dev, "Removed from deferred list\n");
>>  		list_del_init(&dev->p->deferred_probe);
>> -		kfree(dev->p->deferred_probe_reason);
>> -		dev->p->deferred_probe_reason = NULL;
>> +		__device_set_deferred_probe_reason(dev, NULL);
>>  	}
>>  	mutex_unlock(&deferred_probe_mutex);
>>  }
>> @@ -220,11 +224,12 @@ void device_unblock_probing(void)
>>  void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
>>  {
>>  	const char *drv = dev_driver_string(dev);
>> +	char *reason;
>>  
>>  	mutex_lock(&deferred_probe_mutex);
>>  
>> -	kfree(dev->p->deferred_probe_reason);
>> -	dev->p->deferred_probe_reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
>> +	reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
> 
> No error checking?

There wasn't any before and I think silent failure to set the defer reason
is completely adequate behavior.

Cheers,
Ahmad

> 
> :(
> 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |