cvs commit: src/sbin/kldunload kldunload.8 kldunload.c

[Nate Lawson]

Poul-Henning Kamp wrote:
>   Give kldunload a -f(orce) argument.
>   
>   Add a MOD_QUIESCE event for modules.  This should return error (EBUSY)
>   of the module is in use.
>   
>   MOD_UNLOAD should now only fail if it is impossible (as opposed to
>   inconvenient) to unload the module.  Valid reasons are memory references
>   into the module which cannot be tracked down and eliminated.
>   
>   When kldunloading, we abandon if MOD_UNLOAD fails, and if -force is
>   not given, MOD_QUIESCE failing will also prevent the unload.

Hmmm, a quick check of the archives shows that I missed your discussion 
of this on Thursday/Friday when I was on vacation.  (Including the 
extremely useful naming replies!)

Have you kept up on the newbus discussions?  The tentative plan was to 
add quiesce functionality to it as part of device_detach().  Doing it at 
the module layer is a bit too low since there are events that can 
trigger a detach but not an unload.  For instance, any driver compiled 
into the kernel for an ejectable device will never be unloaded, but 
certainly should quiesce/detach when the device is ejected.  Getting it 
right in newbus automatically fixes the problem you're trying to solve 
since a module unload always triggers a call to device_detach() but not 
vice versa.

I think duplicating this at multiple layers is not a good idea and the 
module level is not the right layer to implement it.

-- 
-Nate