[$] Page pinning and filesystems

It would have been surprising indeed if the 2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM) did not include a
session working toward solutions to the longstanding problems with
get_user_pages(), an internal function that locks user-space pages
in memory for access by the kernel. The issue has, after all, come up numerous times
over the years. This year's event duly contained a session in the joint
filesystem and memory-management track, led by John Hubbard, with a focus
on page pinning and how it interacts with filesystems.