Messages in this thread | | | Date | Mon, 12 Aug 2019 14:48:55 -0700 | From | Ira Weiny <> | Subject | Re: [RFC PATCH v2 15/19] mm/gup: Introduce vaddr_pin_pages() |
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On Mon, Aug 12, 2019 at 09:28:14AM -0300, Jason Gunthorpe wrote: > On Fri, Aug 09, 2019 at 03:58:29PM -0700, ira.weiny@intel.com wrote: > > From: Ira Weiny <ira.weiny@intel.com> > > > > The addition of FOLL_LONGTERM has taken on additional meaning for CMA > > pages. > > > > In addition subsystems such as RDMA require new information to be passed > > to the GUP interface to track file owning information. As such a simple > > FOLL_LONGTERM flag is no longer sufficient for these users to pin pages. > > > > Introduce a new GUP like call which takes the newly introduced vaddr_pin > > information. Failure to pass the vaddr_pin object back to a vaddr_put* > > call will result in a failure if pins were created on files during the > > pin operation. > > Is this a 'vaddr' in the traditional sense, ie does it work with > something returned by valloc?
...or malloc in user space, yes. I think the idea is that it is a user virtual address.
> > Maybe another name would be better?
Maybe, the name I had was way worse... So I'm not even going to admit to it...
;-)
So I'm open to suggestions. Jan gave me this one, so I figured it was safer to suggest it...
:-D
> > I also wish GUP like functions took in a 'void __user *' instead of > the unsigned long to make this clear :\
Not a bad idea. But I only see a couple of call sites who actually use a 'void __user *' to pass into GUP... :-/
For RDMA the address is _never_ a 'void __user *' AFAICS.
For the new API, it may be tractable to force users to cast to 'void __user *' but it is not going to provide any type safety.
But it is easy to change in this series.
What do others think?
Ira
> > Jason >
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