Michael S. Tsirkin wrote: > On Tue, Jun 02, 2009 at 01:41:05PM -0400, Gregory Haskins wrote: > >>> And having close not clean up the state unless you do an ioctl first is >>> very messy IMO - I don't think you'll find any such examples in kernel. >>> >>> >>> >> I agree, and that is why I am advocating this POLLHUP solution. It was >> only this other way to begin with because the technology didn't exist >> until Davide showed me the light. >> >> Problem with your request is that I already looked into what is >> essentially a bi-directional reference problem (for a different reason) >> when I started the POLLHUP series. Its messy to do this in a way that >> doesn't negatively impact the fast path (introducing locking, etc) or >> make my head explode making sure it doesn't race. Afaict, we would need >> to solve this problem to do what you are proposing (patches welcome). >> >> If this hybrid decoupled-deassign + unified-close is indeed an important >> feature set, I suggest that we still consider this POLLHUP series for >> inclusion, and then someone can re-introduce DEASSIGN support in the >> future as a CAP bit extension. That way we at least get the desirable >> close() properties that we both seem in favor of, and get this advanced >> use case when we need it (and can figure out the locking design). >> >> > > FWIW, I took a look and yes, it is non-trivial. > I concur, we can always add the deassign ioctl later. > > > > Sounds good, Michael. Thanks! -Greg
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