Re: [PATCH 2/2] usb: misc: refactor code

From: Alan Stern
Date: Mon Apr 03 2017 - 17:06:28 EST


On Mon, 3 Apr 2017, Gustavo A. R. Silva wrote:

> Code refactoring to make the flow easier to follow.
>
> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
> ---
> 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?

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

And here?

>
> 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?

> + 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?

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;
>