[openib-general] Re: [PATCH 11/16] IB uverbs: add mthca mmap support

[Michael S. Tsirkin]

Quoting r. Roland Dreier <rolandd at cisco.com>:
> Subject: Re: [PATCH 11/16] IB uverbs: add mthca mmap support
> 
>     Andrew> What's the thinking behind the VM_DONTCOPY there?
> 
> As I said before, I don't think the thinking behind VM_DONTCOPY was
> correct thinking.  Let's take it out.

Roland, I think VM_DONTCOPY is needed here.

If a process forks, we must prevent the child from accessing
the parent's hardware page. Otherwise the child can corrupt
the parent's queues since the hardware wont be able to distinguish
between parent and child.

Does this make sense?

-- 
MST