On Wed, Jul 26, 2017 at 09:08:00AM -0700, Dan Williams wrote: > Another question, does ->rw_page() really buy us that much with the > pmem driver? If applications want to enjoy the lowest latency access > they can just use DAX. There's now only 4 drivers that use rw_page > since nvme dropped its usage and I'd be inclined to just rip it out. nvme never supported rw_page (there was a page for it, but it fortunately never got merged). rw_page are massive pain the ass and the method should go away. For make_request drivers that actually operate synchronous (e.g. the ramdisk) it's not much of a benefit, and even for normally asynchronous drivers like nvme the block layer polling interface is much more suitable.
