patch: portable dirhash

[Robert Watson]

On Wed, 17 Dec 2003, Robert Watson wrote:

> On Wed, 17 Dec 2003, Alexander Kabaev wrote:
> 
> > On Tue, 16 Dec 2003 22:12:08 -0500 (EST)
> > Ted Unangst <tedu at zeitbombe.org> wrote:
> > 
> > > can somebody please review/commit this to freebsd?  it is most of the 
> > > differences to permit openbsd to use the code.  it should not change
> > > the code in any functional way.
> > 
> > I do not think there is any point in this code ever hitting FreeBSD CVS
> > repository. Rather, OpenBSD should just take cleaned-out copy of this
> > code and be done with it. 
> 
> Well, it's true the #ifdef OpenBSD's probably don't help the readability
> of our code, abstracting a step by using macros to wrap specific locking
> primitives is a widely used approach in the FreeBSD tree, especially
> where it's not clear a final locking strategy has been developed due to
> a lack of profiling.  For example, in both the network code and process
> management code, we wrap mutexes/sxlocks in macros to avoid committing
> to either, and to make changing the strategy easier.  I wouldn't object
> to our adopting the macro wrapping, which would have the side effect of
> helping the OpenBSD patch size a lot also, even leaving out the
> #ifdef's. 

That said, LOCK() is a terrible name for a macro. :-)  If anything, it
should be DIRHASH_LOCK() or the like. 

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Senior Research Scientist, McAfee Research