On Mon, Aug 12, 2019 at 02:48:55PM -0700, Ira Weiny wrote: > 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(a)intel.com wrote: > > > From: Ira Weiny <ira.weiny(a)intel.com&gt; > > > > > > 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. valloc is a kernel call

> So I'm open to suggestions. Jan gave me this one, so I figured it was safer to > suggest it... Should have the word user in it, imho

> > 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. That is actually a bug, converting from u64 to a 'user VA' needs to go through u64_to_user_ptr().