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

[Chanh Nguyen <chanh@xxxxxxxxxxxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxxxxxxxxx>
>
> Tested-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
>
> 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