linux-kernel - Re: [PATCH 2/2] usb: misc: refactor code

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Date:   Mon, 03 Apr 2017 21:11:25 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Alan Stern <stern@...land.harvard.edu>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <felipe.balbi@...ux.intel.com>,
        Peter Chen <peter.chen@....com>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Peter Senna Tschudin <peter.senna@...il.com>
Subject: Re: [PATCH 2/2] usb: misc: refactor code

Hi Alan,

Quoting Alan Stern <stern@...land.harvard.edu>:

> On Mon, 3 Apr 2017, Gustavo A. R. Silva wrote:
>
>> Code refactoring to make the flow easier to follow.
>>
>> Cc: Alan Stern <stern@...loand.harvard.edu>
>> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>> Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
>> ---
>>  drivers/usb/misc/usbtest.c | 67  
>> +++++++++++++++++++++-------------------------
>>  1 file changed, 30 insertions(+), 37 deletions(-)
>>
>> diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
>> index 7bfb6b78..382491e 100644
>> --- a/drivers/usb/misc/usbtest.c
>> +++ b/drivers/usb/misc/usbtest.c
>> @@ -124,18 +124,32 @@ static struct usb_device  
>> *testdev_to_usbdev(struct usbtest_dev *test)
>>
>>   
>> /*-------------------------------------------------------------------------*/
>>
>> +static inline void endpoint_update(int edi,
>> +				   struct usb_host_endpoint **in,
>> +				   struct usb_host_endpoint **out,
>> +				   struct usb_host_endpoint *e)
>> +{
>> +	if (edi) {
>> +		if (!*in)
>> +			*in = e;
>> +	} else {
>> +		if (!*out)
>> +			*out = e;
>> +	}
>> +}
>> +
>>  static int
>>  get_endpoints(struct usbtest_dev *dev, struct usb_interface *intf)
>>  {
>> -	int				tmp;
>> -	struct usb_host_interface	*alt;
>> -	struct usb_host_endpoint	*in, *out;
>> -	struct usb_host_endpoint	*iso_in, *iso_out;
>> -	struct usb_host_endpoint	*int_in, *int_out;
>> -	struct usb_device		*udev;
>> +	int                             tmp;
>> +	struct usb_host_interface       *alt;
>> +	struct usb_host_endpoint        *in, *out;
>> +	struct usb_host_endpoint        *iso_in, *iso_out;
>> +	struct usb_host_endpoint        *int_in, *int_out;
>> +	struct usb_device               *udev;
>
> What's the difference between these 6 lines you added and the 6 lines
> that were there originally?
>

Yeah, well, certainly none at all. This is what happened: I created a  
local copy of my changes(this piece of code included) and fixed some  
issues in a previous patch, then I did a git revert and moved my  
changes back to the original file. During this process the tabs were  
replaced with spaces in the original file, then I had to add the tabs  
again and this was the resulting patch.

>>  	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
>> -		unsigned	ep;
>> +		unsigned        ep;
>
> And here?
>

Same as above.

>>
>>  		in = out = NULL;
>>  		iso_in = iso_out = NULL;
>> @@ -150,48 +164,27 @@ get_endpoints(struct usbtest_dev *dev, struct  
>> usb_interface *intf)
>>  		 * ignore other endpoints and altsettings.
>>  		 */
>>  		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
>> -			struct usb_host_endpoint	*e;
>> +			struct usb_host_endpoint        *e;
>
> And here?
>

Same as above.

>> +			int edi;
>>
>>  			e = alt->endpoint + ep;
>> +			edi = usb_endpoint_dir_in(&e->desc);
>> +
>>  			switch (usb_endpoint_type(&e->desc)) {
>>  			case USB_ENDPOINT_XFER_BULK:
>> -				break;
>> +				endpoint_update(edi, &in, &out, e);
>> +				continue;
>>  			case USB_ENDPOINT_XFER_INT:
>>  				if (dev->info->intr)
>> -					goto try_intr;
>> +					endpoint_update(edi, &int_in, &int_out, e);
>>  				continue;
>>  			case USB_ENDPOINT_XFER_ISOC:
>>  				if (dev->info->iso)
>> -					goto try_iso;
>> -				/* FALLTHROUGH */
>> +					endpoint_update(edi, &iso_in, &iso_out, e);
>> +				/* fall through */
>
> Why change the comment?
>

Oh, I based this change in the following comment to another patch I  
sent some weeks ago:
https://lkml.org/lkml/2017/2/10/293

It is due to Coding Style.

> Alan Stern
>
>>  			default:
>>  				continue;
>>  			}
>> -			if (usb_endpoint_dir_in(&e->desc)) {
>> -				if (!in)
>> -					in = e;
>> -			} else {
>> -				if (!out)
>> -					out = e;
>> -			}
>> -			continue;
>> -try_intr:
>> -			if (usb_endpoint_dir_in(&e->desc)) {
>> -				if (!int_in)
>> -					int_in = e;
>> -			} else {
>> -				if (!int_out)
>> -					int_out = e;
>> -			}
>> -			continue;
>> -try_iso:
>> -			if (usb_endpoint_dir_in(&e->desc)) {
>> -				if (!iso_in)
>> -					iso_in = e;
>> -			} else {
>> -				if (!iso_out)
>> -					iso_out = e;
>> -			}
>>  		}
>>  		if ((in && out)  ||  iso_in || iso_out || int_in || int_out)
>>  			goto found;
>>

Thanks for your comments.
--
Gustavo A. R. Silva