On Tue, Aug 13, 2019 at 08:47:06AM -0300, Jason Gunthorpe wrote: > 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@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. > > valloc is a kernel call Oh... I thought you meant this: https://linux.die.net/man/3/valloc > > > 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 Fair enough... user_addr_pin_pages(void __user * addr, ...) ? uaddr_pin_pages(void __user * addr, ...) ? I think I like uaddr... > > > > 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(). Fair enough. But there are a lot of call sites throughout the kernel who have the same bug... I'm ok with forcing u64_to_user_ptr() to use this new call if others are. Ira
