Re: [PATCH v9 0/6] MAP_DIRECT for DAX userspace flush

On Fri, Oct 13, 2017 at 10:38:22AM -0600, Jason Gunthorpe wrote:

quoted

scheme specific to RDMA which seems like a waste to me when we can
generically signal an event on the fd for any event that effects any
of the vma's on the file. The FL_LAYOUT lease impacts the entire file,
so as far as I can see delaying the notification until MR-init is too
late, too granular, and too RDMA specific.

But for RDMA a FD is not what we care about - we want the MR handle so
the app knows which MR needs fixing.

Yes.  Although the fd for the ibX device might be a good handle to
transport that information, unlike the fd for the mapped file.