On Wed, Aug 26, 2015 at 09:39:18PM +0000, Williams, Dan J wrote: > On Wed, 2015-08-26 at 14:46 +0200, Christoph Hellwig wrote: > > On Tue, Aug 25, 2015 at 09:28:13PM -0400, Dan Williams wrote: > > > Given that: > > > > > > 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. > > > > Agreed, we can drop this until the first user arrives. > > > Also if the page_map gets exposed in a header the name is a bit too generic. > > memremap_map maybe? > > Done, and in the patch below I hide the internal implementation details > of page_map in kernel/memremap.c and only expose the percpu_ref in the > public memremap_map. Yes, that looks good once we're getting the users for it. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>