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@xxxxxxxxx wrote: > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > 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 >
