linux-kernel - Re: [PATCH v5] USB hub_probe: rework ugly goto-into-compound-statement

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Date:   Mon, 14 Nov 2016 07:50:54 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Eugene Korenevsky <ekorenevsky@...il.com>,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        Baolin Wang <baolin.wang@...aro.org>
Subject: Re: [PATCH v5] USB hub_probe: rework ugly
 goto-into-compound-statement

On Sun, Nov 13, 2016 at 03:53:58PM +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@...il.com>
> ---
> 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 | 35 ++++++++++++++++++-----------------
>  1 file changed, 18 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index cbb1467..1a316a1 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1722,10 +1722,25 @@ 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 it's not an interrupt in endpoint, we'd better punt! */
> +	return usb_endpoint_is_int_in(&desc->endpoint[0].desc) != 0;

Also, the comment should say:
	/* If the first endpoint is not interrupt IN, we... */