Make MOD_QUIESCE a bit more useful..

[M. Warner Losh]

In message: <200808091637.33820.jhb at freebsd.org>
            John Baldwin <jhb at FreeBSD.org> writes:
: So currently the MOD_QUIESCE event is posted to a module when unloading a kld 
: so it can veto non-forced unloads.  However, the current implementation in 
: the kernel linker is to run through all the modules in a file, posting 
: MOD_QUIESCE followed by MOD_UNLOAD on each module serially.  Thus, if you 
: have multiple modules in a single kld and one of the modules veto's an unload 
: request via MOD_QUIESCE, you don't know as the module author if any of your 
: modules were unloaded via MOD_UNLOAD or not.  I think a better approach would 
: be to change the kernel linker to invoke MOD_QUIESCE on all modules in a 
: single pass first.  If none of those fail (or it's a forced unload), then it 
: can do a second pass invoking MOD_UNLOAD on all the modules.

That sounds great to me.  I'm a bit surprised it is implemented the
way you say...

Warner