On Tue, Aug 25, 2015 at 09:28:13PM -0400, Dan Williams wrote:
1/ device ->remove() can not be failed
2/ a pmem device may be unbound at any time
3/ we do not know what other parts of the kernel are actively using a
'struct page' from devm_memremap_pages()
...provide a facility for active usages of device memory to block pmem
device unbind. With a percpu_ref it should be feasible to take a
reference on a per-I/O or other high frequency basis.
Without a caller of get_page_map this is just adding dead code. I'd
suggest to group it in a series with that caller.
Also if the page_map gets exposed in a header the name is a bit too generic.