Re: CVS commit: src/sys/dev/scsipi

[Warner Losh <imp%bsdimp.com@localhost>]

On Apr 19, 2012, at 6:03 PM, matthew green wrote:
>> But that's a problem with autoconf not dealing with non-MPSAFE drivers,
>> not the driver themselve (they were working before the MP changes, they
>> should continue to work as-is). If you want autoconf to not run
>> under the KERNEL_LOCK when not needed, then is has to be extended so that
>> MPSAFE drivers can register themselves as MPSAFE, so that non-MPSAFE
>> drivers are still called with KERNEL_LOCK.
> 
> it seems the wrong answer to me.  instead of fixing the one or
> two drivers you've found problems in, you want to add more
> infrastructure (IMO clutter) to the system and patch all the
> drivers that *are* ok.  considering that this problem is
> very specific to scsipi, i don't think that is a viable
> solution.

FreeBSD started out with MPSAFE and then went to NEEDS_GIANT as flags for the 
drivers.  I'm with Matthew: patch the drivers that are broken (or not known to 
be safe) and then you have a convenient thing to grep for when you want to 
expand the drivers that are safe.  Much better that way, and it turned out to 
be a big win in FreeBSD when we went from opt-in MPSAFE to out-out...

Warner