[PATCH v1 1/1] usb: gadget: Use correct APIs and data types for UUID handling

[PATCH v1 1/1] usb: gadget: Use correct APIs and data types for UUID handling

[Andy Shevchenko]

We have two types for UUIDs depending on the byte ordering.
Instead of explaining how bytes should go over the wire,
use dedicated APIs and data types. This removes a confusion
over the byte ordering.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/usb/gadget/composite.c | 4 ++--
 include/linux/usb/webusb.h     | 9 +++------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 8e2603688016..fa7dd6cf014d 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -829,7 +829,7 @@ static int bos_desc(struct usb_composite_dev *cdev)
 	if (cdev->use_webusb) {
 		struct usb_plat_dev_cap_descriptor *webusb_cap;
 		struct usb_webusb_cap_data *webusb_cap_data;
-		uuid_t webusb_uuid = WEBUSB_UUID;
+		guid_t webusb_uuid = WEBUSB_UUID;
 
 		webusb_cap = cdev->req->buf + le16_to_cpu(bos->wTotalLength);
 		webusb_cap_data = (struct usb_webusb_cap_data *) webusb_cap->CapabilityData;
@@ -841,7 +841,7 @@ static int bos_desc(struct usb_composite_dev *cdev)
 		webusb_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
 		webusb_cap->bDevCapabilityType = USB_PLAT_DEV_CAP_TYPE;
 		webusb_cap->bReserved = 0;
-		export_uuid(webusb_cap->UUID, &webusb_uuid);
+		export_guid(webusb_cap->UUID, &webusb_uuid);
 
 		if (cdev->bcd_webusb_version != 0)
 			webusb_cap_data->bcdVersion = cpu_to_le16(cdev->bcd_webusb_version);
diff --git a/include/linux/usb/webusb.h b/include/linux/usb/webusb.h
index b430d84357f3..fe43020b4a48 100644
--- a/include/linux/usb/webusb.h
+++ b/include/linux/usb/webusb.h
@@ -11,15 +11,12 @@
 #include "uapi/linux/usb/ch9.h"
 
 /*
- * little endian PlatformCapablityUUID for WebUSB
+ * Little Endian PlatformCapablityUUID for WebUSB
  * 3408b638-09a9-47a0-8bfd-a0768815b665
- * to identify Platform Device Capability descriptors as referring to WebUSB
- *
- * the UUID above MUST be sent over the wire as the byte sequence:
- * {0x38, 0xB6, 0x08, 0x34, 0xA9, 0x09, 0xA0, 0x47, 0x8B, 0xFD, 0xA0, 0x76, 0x88, 0x15, 0xB6, 0x65}.
+ * to identify Platform Device Capability descriptors as referring to WebUSB.
  */
 #define WEBUSB_UUID \
-	UUID_INIT(0x38b60834, 0xa909, 0xa047, 0x8b, 0xfd, 0xa0, 0x76, 0x88, 0x15, 0xb6, 0x65)
+	GUID_INIT(0x3408b638, 0x09a9, 0x47a0, 0x8b, 0xfd, 0xa0, 0x76, 0x88, 0x15, 0xb6, 0x65)
 
 /*
  * WebUSB Platform Capability data
-- 
2.39.0

Re: [PATCH v1 1/1] usb: gadget: Use correct APIs and data types for UUID handling

[Jó Ágila Bitsch]

On Wed, Jan 25, 2023 at 3:34 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> We have two types for UUIDs depending on the byte ordering.
> Instead of explaining how bytes should go over the wire,
> use dedicated APIs and data types. This removes a confusion
> over the byte ordering.

Thanks for pointing this out. I was unaware of the exact UUID
functions, as I'm still quite a newbie here.

I compiled and tested your patch in my test setup and it works perfectly.

>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/usb/gadget/composite.c | 4 ++--
>  include/linux/usb/webusb.h     | 9 +++------
>  2 files changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 8e2603688016..fa7dd6cf014d 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -829,7 +829,7 @@ static int bos_desc(struct usb_composite_dev *cdev)
>         if (cdev->use_webusb) {
>                 struct usb_plat_dev_cap_descriptor *webusb_cap;
>                 struct usb_webusb_cap_data *webusb_cap_data;
> -               uuid_t webusb_uuid = WEBUSB_UUID;
> +               guid_t webusb_uuid = WEBUSB_UUID;
>
>                 webusb_cap = cdev->req->buf + le16_to_cpu(bos->wTotalLength);
>                 webusb_cap_data = (struct usb_webusb_cap_data *) webusb_cap->CapabilityData;
> @@ -841,7 +841,7 @@ static int bos_desc(struct usb_composite_dev *cdev)
>                 webusb_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
>                 webusb_cap->bDevCapabilityType = USB_PLAT_DEV_CAP_TYPE;
>                 webusb_cap->bReserved = 0;
> -               export_uuid(webusb_cap->UUID, &webusb_uuid);
> +               export_guid(webusb_cap->UUID, &webusb_uuid);
>
>                 if (cdev->bcd_webusb_version != 0)
>                         webusb_cap_data->bcdVersion = cpu_to_le16(cdev->bcd_webusb_version);
> diff --git a/include/linux/usb/webusb.h b/include/linux/usb/webusb.h
> index b430d84357f3..fe43020b4a48 100644
> --- a/include/linux/usb/webusb.h
> +++ b/include/linux/usb/webusb.h
> @@ -11,15 +11,12 @@
>  #include "uapi/linux/usb/ch9.h"
>
>  /*
> - * little endian PlatformCapablityUUID for WebUSB
> + * Little Endian PlatformCapablityUUID for WebUSB
>   * 3408b638-09a9-47a0-8bfd-a0768815b665
> - * to identify Platform Device Capability descriptors as referring to WebUSB
> - *
> - * the UUID above MUST be sent over the wire as the byte sequence:
> - * {0x38, 0xB6, 0x08, 0x34, 0xA9, 0x09, 0xA0, 0x47, 0x8B, 0xFD, 0xA0, 0x76, 0x88, 0x15, 0xB6, 0x65}.

This is actually explicitly spelled out this way in the specification:
https://wicg.github.io/webusb/#webusb-platform-capability-descriptor

But I agree, the way you rewrote it is much clearer!

> + * to identify Platform Device Capability descriptors as referring to WebUSB.
>   */
>  #define WEBUSB_UUID \
> -       UUID_INIT(0x38b60834, 0xa909, 0xa047, 0x8b, 0xfd, 0xa0, 0x76, 0x88, 0x15, 0xb6, 0x65)
> +       GUID_INIT(0x3408b638, 0x09a9, 0x47a0, 0x8b, 0xfd, 0xa0, 0x76, 0x88, 0x15, 0xb6, 0x65)

Yes, this is definitely more readable.

>
>  /*
>   * WebUSB Platform Capability data
> --
> 2.39.0
>

Re: [PATCH v1 1/1] usb: gadget: Use correct APIs and data types for UUID handling

[Andy Shevchenko]

On Wed, Jan 25, 2023 at 06:31:36PM +0100, Jó Ágila Bitsch wrote:
> On Wed, Jan 25, 2023 at 3:34 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> >
> > We have two types for UUIDs depending on the byte ordering.
> > Instead of explaining how bytes should go over the wire,
> > use dedicated APIs and data types. This removes a confusion
> > over the byte ordering.
> 
> Thanks for pointing this out. I was unaware of the exact UUID
> functions, as I'm still quite a newbie here.
> 
> I compiled and tested your patch in my test setup and it works perfectly.

Thanks for the testing. According to Submitting Patches documentation
you can provide a formal Tested-by tag.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1 1/1] usb: gadget: Use correct APIs and data types for UUID handling

[Jó Ágila Bitsch]

On Wed, Jan 25, 2023 at 9:01 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Jan 25, 2023 at 06:31:36PM +0100, Jó Ágila Bitsch wrote:
> > On Wed, Jan 25, 2023 at 3:34 PM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > >
> > > We have two types for UUIDs depending on the byte ordering.
> > > Instead of explaining how bytes should go over the wire,
> > > use dedicated APIs and data types. This removes a confusion
> > > over the byte ordering.
> >
> > Thanks for pointing this out. I was unaware of the exact UUID
> > functions, as I'm still quite a newbie here.
> >
> > I compiled and tested your patch in my test setup and it works perfectly.
>
> Thanks for the testing. According to Submitting Patches documentation
> you can provide a formal Tested-by tag.

Thanks for pointing this out to me.

I'm not really sure how to do that though.
On https://docs.kernel.org/process/submitting-patches.html#reviewer-s-statement-of-oversight,
it says:
> Both Tested-by and Reviewed-by tags, once received on mailing list from tester or reviewer, should be added by author to the applicable patches when sending next versions.

So I guess you could do that at your convenience on any next version.
Or is it already ok, if I just add the following line in my comment?

Tested-By: Jó Ágila Bitsch <jgilab@gmail.com>

I'm still quite a newbie in the kernel development community, so
thanks for bearing with my ignorance :-)

Best regards and thanks a lot,
Jó


>
> --
> With Best Regards,
> Andy Shevchenko
>
>

Re: [PATCH v1 1/1] usb: gadget: Use correct APIs and data types for UUID handling

[Andy Shevchenko]

On Wed, Jan 25, 2023 at 10:54:58PM +0100, Jó Ágila Bitsch wrote:
> On Wed, Jan 25, 2023 at 9:01 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Wed, Jan 25, 2023 at 06:31:36PM +0100, Jó Ágila Bitsch wrote:
> > > On Wed, Jan 25, 2023 at 3:34 PM Andy Shevchenko
> > > <andriy.shevchenko@linux.intel.com> wrote:

...

> > > I compiled and tested your patch in my test setup and it works perfectly.
> >
> > Thanks for the testing. According to Submitting Patches documentation
> > you can provide a formal Tested-by tag.
> 
> Thanks for pointing this out to me.
> 
> I'm not really sure how to do that though.
> On https://docs.kernel.org/process/submitting-patches.html#reviewer-s-statement-of-oversight,
> it says:
> > Both Tested-by and Reviewed-by tags, once received on mailing list from tester or reviewer, should be added by author to the applicable patches when sending next versions.
> 
> So I guess you could do that at your convenience on any next version.

In mine I can only do if you give me that tag. Till this
line the tag is not given, but...

> Or is it already ok, if I just add the following line in my comment?

...this is what is expected to have.

> Tested-By: Jó Ágila Bitsch <jgilab@gmail.com>

And now _if_ I need a new version I will bear this with it. Otherwise
maintainer, who picks up the patch, takes care of gathering these all
together.

> I'm still quite a newbie in the kernel development community, so
> thanks for bearing with my ignorance :-)

So far you are doing good, thanks!

-- 
With Best Regards,
Andy Shevchenko