[openib-general] Re: [PATCH] Ref count user doorbell pages in mthca

[Michael S. Tsirkin]

Quoting r. Roland Dreier <roland at topspin.com>:
> Subject: Re: [PATCH] Ref count user doorbell pages in mthca
> 
>     Michael> Looking at code under mm/, it seems that when you mmap
>     Michael> something, get_file is called on the descriptor (and fput
>     Michael> on close).  So it seems to me the driver's release wont
>     Michael> get called until the app actually unmaps the memory.  If
>     Michael> thats right, there's no issue since the context wont get
>     Michael> closed.
> 
> You may be right.  I need to investigate what happens if a process
> with a UAR mapped forks though.
> 
>  - R.
> 

Why dont we just set VM_DONTCOPY?

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MST