Re: [PATCH 4/5] usb/gadget: don't deploy SS descriptors if SS is not enabled.

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

On 12-04-2011 23:34, Sebastian Andrzej Siewior wrote:

> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>   drivers/usb/gadget/composite.c |    4 ++++
>   1 files changed, 4 insertions(+), 0 deletions(-)

> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 92cc238..ac30e2f 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -74,10 +74,12 @@ MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");
>   static char composite_manufacturer[50];
>
>   /* Default endpoint companion descriptor */
> +#ifdef CONFIG_USB_GADGET_SUPERSPEED
>   static struct usb_ss_ep_comp_descriptor default_ep_comp_desc = {
>   		.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
>   		.bLength = sizeof(struct usb_ss_ep_comp_descriptor),
>   };
> +#endif
>
>   /**
>    * usb_create_ss_descriptors() - Generate SuperSpeed descriptors
> @@ -93,6 +95,7 @@ static struct usb_ss_ep_comp_descriptor default_ep_comp_desc = {
>    */
>   void usb_create_ss_descriptors(struct usb_function *f)
>   {
> +#ifdef CONFIG_USB_GADGET_SUPERSPEED
>   	struct usb_ss_ep_comp_descriptor	*ep_comp_desc;
>   	struct usb_endpoint_descriptor		*ep_desc;
>   	struct usb_descriptor_header		**src = f->hs_descriptors;
> @@ -185,6 +188,7 @@ void usb_create_ss_descriptors(struct usb_function *f)
>   	 */
>   	*tmp = NULL;
>   	f->ss_desc_allocated = true;
> +#endif

    Documentation/SubmittingPatches says this:

2) #ifdefs are ugly

Code cluttered with ifdefs is difficult to read and maintain.  Don't do
it.  Instead, put your ifdefs in a header, and conditionally define
'static inline' functions, or macros, which are used in the code.
Let the compiler optimize away the "no-op" case.

Simple example, of poor code:

	dev = alloc_etherdev (sizeof(struct funky_private));
	if (!dev)
		return -ENODEV;
	#ifdef CONFIG_NET_FUNKINESS
	init_funky_net(dev);
	#endif

Cleaned-up example:

(in header)
	#ifndef CONFIG_NET_FUNKINESS
	static inline void init_funky_net (struct net_device *d) {}
	#endif

(in the code itself)
	dev = alloc_etherdev (sizeof(struct funky_private));
	if (!dev)
		return -ENODEV;
	init_funky_net(dev);

WBR, Sergei