a code reduction function addition to cam_xpt

[Bruce Evans]

On Mon, 4 Dec 2006, Ade Lovett wrote:

> On Dec 04, 2006, at 20:27 , mjacob at freebsd.org wrote:
>>> On Dec 04, 2006, at 19:27 , mjacob at freebsd.org wrote:
>>>> IOCCC?
>>> 
>>> http://www.ioccc.org/

Or just google it.

>>> Consider this another vote for "function" ;)
>> 
>> Bruce is usually less indirect. What gives?

You haven't talked to me enough :-).

> Multi-line #define's are 'orrible (IMO) -- of course, our tree is littered 
> with them, but it's highly preferable to have a function over a define, 
> particularly when it comes to reading the code n months later, trying to 
> track something down.  In this particular case, the minimal overhead of 
> calling a function rather than having it inline (via #define) is vastly 
> outweighed by code-readability, and reduction in kernel size.

And in many cases reducing the kernel size also reduces time due to it
reducing cache misses.  Here I think the code is so rarely executed that
neither space or time efficiency really matters.

Bruce