Attempt VMA lock-based page fault handling first, and fall back to the
existing mmap_lock-based handling if that fails.

Link: https://lkml.kernel.org/r/20230227173632.3292573-31-surenb@google.comSigned-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>