Re: [PATCH v3 4/6] usb: gadget: f_fs: add a device reference of usb_gadget->dev

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Mar 27, 2023 at 06:12:18PM +0800, Linyu Yuan wrote:
> It is known that dev_vdbg() macro can accept NULL or non-NULL dev pointer.
> 
> Add a struct device *dev member in struct ffs_data, set it to NULL before
> binding or after unbinding to a usb_gadget, set it reference of usb_gadget
> ->dev when bind success.
> 
> Then it can help replace private pr_vdebug() to dev_vdbg() consistently.
> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> ---
> v3: new patch in this version
> 
>  drivers/usb/gadget/function/f_fs.c | 3 +++
>  drivers/usb/gadget/function/u_fs.h | 1 +
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index a4051c8..25461f1 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -1722,6 +1722,7 @@ static struct ffs_data *ffs_data_new(const char *dev_name)
>  		return NULL;
>  	}
>  
> +	ffs->dev = NULL;
>  	refcount_set(&ffs->ref, 1);
>  	atomic_set(&ffs->opened, 0);
>  	ffs->state = FFS_READ_DESCRIPTORS;
> @@ -1831,6 +1832,7 @@ static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
>  	}
>  
>  	ffs->gadget = cdev->gadget;
> +	ffs->dev = &cdev->gadget->dev;
>  	ffs_data_get(ffs);
>  	return 0;
>  }
> @@ -1843,6 +1845,7 @@ static void functionfs_unbind(struct ffs_data *ffs)
>  		mutex_lock(&ffs->mutex);
>  		usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
>  		ffs->ep0req = NULL;
> +		ffs->dev = NULL;
>  		ffs->gadget = NULL;
>  		clear_bit(FFS_FL_BOUND, &ffs->flags);
>  		mutex_unlock(&ffs->mutex);
> diff --git a/drivers/usb/gadget/function/u_fs.h b/drivers/usb/gadget/function/u_fs.h
> index 4b3365f..c5f6167 100644
> --- a/drivers/usb/gadget/function/u_fs.h
> +++ b/drivers/usb/gadget/function/u_fs.h
> @@ -146,6 +146,7 @@ enum ffs_setup_state {
>  
>  struct ffs_data {
>  	struct usb_gadget		*gadget;
> +	struct device			*dev;

No, sorry, this is not correct.

You already have a struct device right there in the struct usb_gadget.
Use that one instead, as you are just setting this pointer to the same
value (see above where you set it.)

thanks,

greg k-h