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SubjectRe: [PATCH v6] USB hub_probe: rework ugly goto-into-compound-statement
On Sat, Nov 19, 2016 at 09:55:45AM +0300, Eugene Korenevsky wrote:
> Rework smelling code (goto inside compound statement). Perhaps this is
> legacy. Anyway such code is not appropriate for Linux kernel.
>
> Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
> ---
> Changes in v6: more pedantic conversion from `int` to `bool`; fix comment
> Changes in v5: make `bool` a return type of `hub_check_descriptor_sanity()`
> Changes in v4: fix typo
> Changes in v3: extract the code to static function
> Changes in v2: fix spaces instead of tab, add missing 'Signed-off-by'
>
> drivers/usb/core/hub.c | 38 +++++++++++++++++++++-----------------
> 1 file changed, 21 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index cbb1467..dbebfe4 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1722,10 +1722,28 @@ static void hub_disconnect(struct usb_interface *intf)
> kref_put(&hub->kref, hub_release);
> }
>
> +static bool hub_check_descriptor_sanity(struct usb_host_interface *desc)
> +{
> + /* Some hubs have a subclass of 1, which AFAICT according to the */
> + /* specs is not defined, but it works */
> + if (desc->desc.bInterfaceSubClass != 0 &&
> + desc->desc.bInterfaceSubClass != 1)
> + return false;
> +
> + /* Multiple endpoints? What kind of mutant ninja-hub is this? */
> + if (desc->desc.bNumEndpoints != 1)
> + return false;
> +
> + /* If the first endpoint is not interrupt IN, we'd better punt! */
> + if (!usb_endpoint_is_int_in(&desc->endpoint[0].desc))
> + return false;
> +
> + return true;
> +}
> +
> static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
> {
> struct usb_host_interface *desc;
> - struct usb_endpoint_descriptor *endpoint;
> struct usb_device *hdev;
> struct usb_hub *hub;
>
> @@ -1800,25 +1818,11 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
> }
> #endif
>
> - /* Some hubs have a subclass of 1, which AFAICT according to the */
> - /* specs is not defined, but it works */
> - if ((desc->desc.bInterfaceSubClass != 0) &&
> - (desc->desc.bInterfaceSubClass != 1)) {
> -descriptor_error:
> + if (!hub_check_descriptor_sanity(desc)) {

Read that line out loud please, and tell me it makes sense:
If not hub_check_descriptor_sanity().

Doesn't:
If not hub_descriptor_is_sane()
make more sense?

thanks,

greg k-h

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