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

[Chanh Nguyen]

On 11/01/2023 16:46, Andrzej Pietrasiewicz wrote:
> Hello,
>
> W dniu 11.01.2023 o 07:51, Chanh Nguyen pisze:
> > 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>
> >
> > ---
> > 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);
>
> This line is 88 chars long, which means you're taking advantage of 
> checkpatch
> allowing 100 columns nowadays. That's absolutely fine. If you collapse 
> the above
> two lines into one, the combined length is exactly 100 chars, so you might
> just as well use a single line. In any case (collapsed or not) you can 
> add my
>
> Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>

Thanks Andrzej for the review.

Just found out the commit title is not totally correct.
It should be "usb: gadget: Append name as suffix to configfs-gadget 
driver names".

I wonder if these issues could be fixed when get merged or should I 
resend a v4 with that two lines collapsed and with the title adjust?

Thanks a lot,
- Chanh

> > +    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);