[PATCH v3] USB: gadget: Add ID numbers to configfs-gadget driver names

[Chanh Nguyen]

On 12/01/2023 14:26, Heikki Krogerus wrote:
> On Wed, Jan 11, 2023 at 01:51:05PM +0700, Chanh Nguyen wrote:
>> It is unable to use configfs to attach more than one gadget. When
>> attaching the second gadget, it always fails and the kernel message
>> prints out:
>>
>> Error: Driver 'configfs-gadget' is already registered, aborting...
>> UDC core: g1: driver registration failed: -16
>>
>> This commit fixes the problem by using the gadget name as a suffix
>> to each configfs_gadget's driver name, thus making the names
>> distinct.
>>
>> Fixes: fc274c1e9973 ("USB: gadget: Add a new bus for gadgets")
>> Signed-off-by: Chanh Nguyen <chanh at os.amperecomputing.com>
> 
> Tested-by: Heikki Krogerus <heikki.krogerus at linux.intel.com>
> 
> Thanks!
> 

Thanks Heikki!

>> ---
>> Changes in v3:
>>    - Use the gadget name as a unique suffix instead     [Andrzej]
>>    - Remove the driver.name allocation by template        [Chanh]
>>    - Update commit message                                [Chanh]
>>
>> Changes in v2:
>>    - Replace scnprintf() by kasprintf() to simplify the code [CJ]
>>    - Move the clean up code from gadgets_drop() to
>>      gadget_info_attr_release()                        [Frank Li]
>>    - Correct the resource free up in gadges_make()   [Alan Stern]
>>    - Remove the unnecessary variable in gadgets_make()    [Chanh]
>>    - Fixes minor grammar issue in commit message          [Chanh]
>> ---
>>   drivers/usb/gadget/configfs.c | 12 ++++++++++--
>>   1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
>> index 96121d1c8df4..0853536cbf2e 100644
>> --- a/drivers/usb/gadget/configfs.c
>> +++ b/drivers/usb/gadget/configfs.c
>> @@ -393,6 +393,7 @@ static void gadget_info_attr_release(struct config_item *item)
>>   	WARN_ON(!list_empty(&gi->string_list));
>>   	WARN_ON(!list_empty(&gi->available_func));
>>   	kfree(gi->composite.gadget_driver.function);
>> +	kfree(gi->composite.gadget_driver.driver.name);
>>   	kfree(gi);
>>   }
>>   
>> @@ -1572,7 +1573,6 @@ static const struct usb_gadget_driver configfs_driver_template = {
>>   	.max_speed	= USB_SPEED_SUPER_PLUS,
>>   	.driver = {
>>   		.owner          = THIS_MODULE,
>> -		.name		= "configfs-gadget",
>>   	},
>>   	.match_existing_only = 1,
>>   };
>> @@ -1623,13 +1623,21 @@ static struct config_group *gadgets_make(
>>   
>>   	gi->composite.gadget_driver = configfs_driver_template;
>>   
>> +	gi->composite.gadget_driver.driver.name = kasprintf(GFP_KERNEL,
>> +							    "configfs-gadget.%s", name);
>> +	if (!gi->composite.gadget_driver.driver.name)
>> +		goto err;
>> +
>>   	gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL);
>>   	gi->composite.name = gi->composite.gadget_driver.function;
>>   
>>   	if (!gi->composite.gadget_driver.function)
>> -		goto err;
>> +		goto out_free_driver_name;
>>   
>>   	return &gi->group;
>> +
>> +out_free_driver_name:
>> +	kfree(gi->composite.gadget_driver.driver.name);
>>   err:
>>   	kfree(gi);
>>   	return ERR_PTR(-ENOMEM);
>> -- 
>> 2.17.1
>