How to do proper locking

[M. Warner Losh]

In message: <200508051329.14767.jhb at FreeBSD.org>
            John Baldwin <jhb at freebsd.org> writes:
: Maybe, but another thing you need to consider is "maintainenance" overhead.  
: Device drivers, especially, should be the simplest parts of the kernel to 
: implement because we want to minimize the potential for screw up in that 
: area.  Having to trust that the same code is going to be duplicated 40 or 50 
: times without any errors versus having it done once in a centralized place 
: where it breaks everyone if it is broken is just insane.  Otherwise, we might 
: as well go write the whole kernel in assembly so we can tweak every last bit 
: out of it. :)

History has shown that when you have to rely on 50 copies of something
being done right, 48 of them will, in fact, have 49 different things
wrong with them.

Warner