Changes since v1: [1] * Kill support for mapping System RAM as a nop. No one uses this functionality and it is broken relative to percpu_ref management.
* Fix percpu_ref teardown. Given that devm_memremap_pages() has strict assumptions about when the percpu_ref is killed, give it responsibility to make the live-dead transition explicitly. (Logan)
* Split the patch that adds HMM support to devm_memremap_pages() from the patch that converts HMM to use devm_memremap_pages(). This caught an incomplete conversion in v1. (Logan)
* Collect Christoph's reviewed-by.
[1]: https://lkml.org/lkml/2018/5/21/1109
---
Hi Andrew, here's v2 to replace the 5 currently in mm. The first and last patch did not change.
For maintainability, as ZONE_DEVICE continues to attract new users, it is useful to keep all users consolidated on devm_memremap_pages() as the interface for create "device pages".
The devm_memremap_pages() implementation was recently reworked to make it more generic for arbitrary users, like the proposed peer-to-peer PCI-E enabling. HMM pre-dated this rework and opted to duplicate devm_memremap_pages() as hmm_devmem_pages_create().
Rework HMM to be a consumer of devm_memremap_pages() directly and fix up the licensing on the exports given the deep dependencies on the mm.
Patches based on v4.17-rc6 where there are no upstream consumers of the HMM functionality.
---
Dan Williams (7): mm, devm_memremap_pages: Mark devm_memremap_pages() EXPORT_SYMBOL_GPL mm, devm_memremap_pages: Kill mapping "System RAM" support mm, devm_memremap_pages: Fix shutdown handling mm, devm_memremap_pages: Add MEMORY_DEVICE_PRIVATE support mm, hmm: Use devm semantics for hmm_devmem_{add,remove} mm, hmm: Replace hmm_devmem_pages_create() with devm_memremap_pages() mm, hmm: Mark hmm_devmem_{add,add_resource} EXPORT_SYMBOL_GPL
Documentation/vm/hmm.txt | 1 drivers/dax/pmem.c | 10 - drivers/nvdimm/pmem.c | 18 +- include/linux/hmm.h | 4 include/linux/memremap.h | 7 + kernel/memremap.c | 85 +++++++--- mm/hmm.c | 307 +++++-------------------------------- tools/testing/nvdimm/test/iomap.c | 21 ++- 8 files changed, 130 insertions(+), 323 deletions(-)