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Message-ID: <09d43174-03fc-abb8-db28-b0fb338492f1@linux.dev>
Date: Fri, 15 Dec 2023 21:23:12 +0800
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Subject: Re: [PATCH] USB: core: Use device_driver directly in struct
 usb_driver and usb_device_driver
To: Greg KH <gregkh@linuxfoundation.org>
Cc: marcel@holtmann.org, johan.hedberg@gmail.com, luiz.dentz@gmail.com,
 wg@grandegger.com, mkl@pengutronix.de, aspriel@gmail.com,
 franky.lin@broadcom.com, hante.meuleman@broadcom.com, kvalo@kernel.org,
 briannorris@chromium.org, mka@chromium.org, johan@kernel.org,
 oneukum@suse.com, stern@rowland.harvard.edu, valentina.manea.m@gmail.com,
 shuah@kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20231215063101.792991-1-yajun.deng@linux.dev>
 <2023121505-dexterity-rectal-8898@gregkh>
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From: Yajun Deng <yajun.deng@linux.dev>
In-Reply-To: <2023121505-dexterity-rectal-8898@gregkh>
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On 2023/12/15 20:40, Greg KH wrote:
> On Fri, Dec 15, 2023 at 02:31:01PM +0800, Yajun Deng wrote:
>> There is usbdrv_wrap in struct usb_driver and usb_device_driver,
>> it contains device_driver and for_devices. for_devices is used to
>> distinguish between device drivers and interface drivers.
> Yes.
>
>> We can compare that if 'drv->probe' is equal to usb_probe_device instead
>> of using for_devices in is_usb_device_driver().
> Why?


For remove struct usbdrv_wrap. As we can see,  other structs use 
device_driver directly.

struct sdio_driver {

... ...

         struct device_driver drv;
};


struct pcie_port_service_driver {

... ...

         struct device_driver driver;
};

and so on ...

So there is no need a wrapper for device_driver if we can implement 
is_usb_device_driver().

>
>> Remove struct usbdrv_wrap, use device_driver directly in struct usb_driver
>> and usb_device_driver. This makes the code more concise.
> Really?  What does this help out with?  Are there future changes that
> require this?


No, just for cleanups and consistency with other structs.

> I'm all for cleanups, but I don't see what this helps with.
>
> Also, you have a coding style issue in this patch, which means I
> couldn't take it anyway:
>
>> +extern int usb_probe_device(struct device *dev);
> We don't do that in .c files :(


It's in drivers/usb/core/usb.h, not in .c files.

>
> thanks,
>
> greg k-h