Re: [KVM PATCH v3 3/3] KVM: Fix races in irqfd using new eventfd_kref_get interface

Davide Libenzi
2009-06-22T18:48:18Z

On Mon, 22 Jun 2009, Michael S. Tsirkin wrote:

> On Mon, Jun 22, 2009 at 11:11:12AM -0700, Davide Libenzi wrote:
> > On Mon, 22 Jun 2009, Michael S. Tsirkin wrote:
> >
> > > Not really, it's impossible to document all races one have thought
> > > about and avoided.
> >
> > Well, when some new code has non-trivial locking/racing logics, you better
> > document it as clearly as possible, akpm announced time ago.
>
> Absolutely. But IMO documentation in the form of "fields A B C are
> protected by lock X" in a single place near field declaration is better
> than "we take lock X here to protect against race with user thread using
> fields A B C" sprinkled all over the code.

Exactly what akpm suggested. A fat comment on top of the C file describing
locking logic and pitfalls.

- Davide