Remove d_thread_t for 8.0

[John Baldwin]

On Wednesday 20 May 2009 10:59:24 am M. Warner Losh wrote:
> In message: <200905121020.18497.jhb at freebsd.org>
>             John Baldwin <jhb at freebsd.org> writes:
> : In the same vein as purging BURN_BRIDGES stuff, is there any objection to 
> : removing d_thread_t from 8.0?  It is intended as a compat shim to reduce 
> : diffs with 4.x.  However, at this point drivers are not actively being 
merged 
> : back to 4.x, so I think it is no longer necessary.
> 
> It was also intended to allow easier sharing for folks that were using
> FreeBSD 4.x, 5.x, etc.  I know that at least one user still has some
> 4.x deployments, but I suspect that they are otherwise off 4.x so it
> might not be a problem for them.  It would be yet another thing to
> change when going from 7.x to 8.x for them...
> 
> We certainly should remove it from the drivers in the tree for 8.0.
> Right now it is used in about a two dozen places.

Even in a shared driver I believe the function prototypes for devsw routines 
would already have to be #ifdef'd due to the 'dev_t' -> 'struct cdev *' 
change which does have a similar foo_t typedef to ease the transition.  Given 
that, any code compiled for 7.0+ is already using a function prototype that 
is not compatible with 4.x and there isn't a need for it to use d_thread_t.  
They can just use 'struct thread *' always when using 'struct cdev *'.

-- 
John Baldwin