Merge tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:

 - Replace pcommit with ADR / directed-flushing.

   The pcommit instruction, which has not shipped on any product, is
   deprecated.  Instead, the requirement is that platforms implement
   either ADR, or provide one or more flush addresses per nvdimm.

   ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
   to the memory controller on a power-fail event.

   Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
   Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
   A flush hint is an mmio address that when written and fenced assures
   that all previous posted writes targeting a given dimm have been
   flushed to media.

 - On-demand ARS (address range scrub).

   Linux uses the results of the ACPI ARS commands to track bad blocks
   in pmem devices.  When latent errors are detected we re-scrub the
   media to refresh the bad block list, userspace can also request a
   re-scrub at any time.

 - Support for the Microsoft DSM (device specific method) command
   format.

 - Support for EDK2/OVMF virtual disk device memory ranges.

 - Various fixes and cleanups across the subsystem.

* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
  libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
  nfit: do an ARS scrub on hitting a latent media error
  nfit: move to nfit/ sub-directory
  nfit, libnvdimm: allow an ARS scrub to be triggered on demand
  libnvdimm: register nvdimm_bus devices with an nd_bus driver
  pmem: clarify a debug print in pmem_clear_poison
  x86/insn: remove pcommit
  Revert "KVM: x86: add pcommit support"
  nfit, tools/testing/nvdimm/: unify shutdown paths
  libnvdimm: move ->module to struct nvdimm_bus_descriptor
  nfit: cleanup acpi_nfit_init calling convention
  nfit: fix _FIT evaluation memory leak + use after free
  tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
  tools/testing/nvdimm: add virtual ramdisk range
  acpi, nfit: treat virtual ramdisk SPA as pmem region
  pmem: kill __pmem address space
  pmem: kill wmb_pmem()
  libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
  fs/dax: remove wmb_pmem()
  libnvdimm, pmem: flush posted-write queues on shutdown
  ...

2 files changed, 10 insertions, 20 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index ef46d3ac5774..1b3c39a7de62 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -395,7 +395,7 @@ prototypes:
 	int (*release) (struct gendisk *, fmode_t);
 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
-	int (*direct_access) (struct block_device *, sector_t, void __pmem **,
+	int (*direct_access) (struct block_device *, sector_t, void **,
 				unsigned long *);
 	int (*media_changed) (struct gendisk *);
 	void (*unlock_native_capacity) (struct gendisk *);
diff --git a/Documentation/nvdimm/btt.txt b/Documentation/nvdimm/btt.txt
index b91443f577dc..e293fb664924 100644
--- a/Documentation/nvdimm/btt.txt
+++ b/Documentation/nvdimm/btt.txt
@@ -256,28 +256,18 @@ If any of these error conditions are encountered, the arena is put into a read
 only state using a flag in the info block.
 
 
-5. In-kernel usage
-==================
+5. Usage
+========
 
-Any block driver that supports byte granularity IO to the storage may register
-with the BTT. It will have to provide the rw_bytes interface in its
-block_device_operations struct:
+The BTT can be set up on any disk (namespace) exposed by the libnvdimm subsystem
+(pmem, or blk mode). The easiest way to set up such a namespace is using the
+'ndctl' utility [1]:
 
-	int (*rw_bytes)(struct gendisk *, void *, size_t, off_t, int rw);
+For example, the ndctl command line to setup a btt with a 4k sector size is:
 
-It may register with the BTT after it adds its own gendisk, using btt_init:
+    ndctl create-namespace -f -e namespace0.0 -m sector -l 4k
 
-	struct btt *btt_init(struct gendisk *disk, unsigned long long rawsize,
-			u32 lbasize, u8 uuid[], int maxlane);
+See ndctl create-namespace --help for more options.
 
-note that maxlane is the maximum amount of concurrency the driver wishes to
-allow the BTT to use.
-
-The BTT 'disk' appears as a stacked block device that grabs the underlying block
-device in the O_EXCL mode.
-
-When the driver wishes to remove the backing disk, it should similarly call
-btt_fini using the same struct btt* handle that was provided to it by btt_init.
-
-	void btt_fini(struct btt *btt);
+[1]: https://github.com/pmem/ndctl