Re: [PATCHv3 net-next 1/3] sunvnet: upgrade to VIO protocol version 1.6

[David Miller <davem@davemloft.net>]

From: David L Stevens <david.stevens@oracle.com>
Date: Sat, 13 Sep 2014 22:39:25 -0400

> 
> 
> On 09/13/2014 04:18 PM, David Miller wrote:
>> From: David L Stevens <david.stevens@oracle.com>
> 
>> static inline bool vio_version_before(struct vio_driver_state *vio,
>> 				      u16 major, u16 minor)
>> {
>> 	u32 have = (u32)vio->major << 16 | vio->minor;
>> 	u32 want = (u32)major << 16 | minor;
>> 
>> 	return have < want;
>> }
>> static inline bool vio_version_after_eq(struct vio_driver_state *vio,
>> 					u16 major, u16 minor)
>> {
>> 	u32 have = (u32)vio->major << 16 | vio->minor;
>> 	u32 want = (u32)major << 16 | minor;
>> 
>> 	return have >= want;
>> }
>> 
>> Something like that.
> 
> Sure. I was thinking about something like:
> 
> #define VIO_VER(major, minor)	(((major)<<16)|(minor))
> 
> change the version struct to a 32-bit int, and do things like:
> 
> 	if (vio->ver > VIO_VER(1,6)) {
> 
> unless you have a preference. (?)

I hate wasting space in a structure just to avoid some harmless
casting in a helper function that is simply trying to optimize
a comparison.

That's why I suggested the inline helpers above, which arguments
are strongly typed.