Testing the dax-device autodetect support revealed a probe failure with
the following result:

    dax0.1: bad offset: 0x8200000 dax disabled

The original pfn-device implementation inferred the alignment from
ilog2(offset), now that the alignment is explicit the is_power_of_2()
needs replacing with a real sanity check against the recorded alignment.
Otherwise the alignment check is useless in the implicit case and only
the minimum size of the offset matters.

This self-consistency check is further validated by the probe path that
will re-check that the offset is large enough to contain all the
metadata required to enable the device.

Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

For autodetecting a previously established dax configuration we need the
info block to indicate block-device vs device-dax mode, and we need to
have the default namespace probe hand-off the configuration to the
dax_pmem driver.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

ida instances allocate some internal memory for ->free_bitmap in
addition to the base 'struct ida'.  Use ida_destroy() to release that
memory at module_exit().
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

This reverts commit 5a023cdb.

The functionality is superseded by the new "Device DAX" facility.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The "Device DAX" core enables dax mappings of performance / feature
differentiated memory.  An open mapping or file handle keeps the backing
struct device live, but new mappings are only possible while the device
is enabled.   Faults are handled under rcu_read_lock to synchronize
with the enabled state of the device.

Similar to the filesystem-dax case the backing memory may optionally
have struct page entries.  However, unlike fs-dax there is no support
for private mappings, or mappings that are not backed by media (see
use of zero-page in fs-dax).

Mappings are always guaranteed to match the alignment of the dax_region.
If the dax_region is configured to have a 2MB alignment, all mappings
are guaranteed to be backed by a pmd entry.  Contrast this determinism
with the fs-dax case where pmd mappings are opportunistic.  If userspace
attempts to force a misaligned mapping, the driver will fail the mmap
attempt.  See dax_dev_check_vma() for other scenarios that are rejected,
like MAP_PRIVATE mappings.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Device DAX is the device-centric analogue of Filesystem DAX
(CONFIG_FS_DAX).  It allows memory ranges to be allocated and mapped
without need of an intervening file system.  Device DAX is strict,
precise and predictable.  Specifically this interface:

1/ Guarantees fault granularity with respect to a given page size (pte,
pmd, or pud) set at configuration time.

2/ Enforces deterministic behavior by being strict about what fault
scenarios are supported.

For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE
support device-dax guarantees that a mapping always behaves/performs the
same once established.  It is the "what you see is what you get" access
mechanism to differentiated memory vs filesystem DAX which has
filesystem specific implementation semantics.

Persistent memory is the first target, but the mechanism is also
targeted for exclusive allocations of performance differentiated memory
ranges.

This commit is limited to the base device driver infrastructure to
associate a dax device with pmem range.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The dax_pmem driver was implementing an empty ->remove() method to
satisfy the nvdimm bus driver that unconditionally calls ->remove().
Teach the core bus driver to check if ->remove() is NULL to remove that
requirement.
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

We want to use the alignment as the allocation and mapping unit.
Previously this information was only useful for establishing the data
offset, but now it is important to remember the granularity for the
later use.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

We may want to subdivide a device-dax range into multiple devices so
that each can have separate permissions or naming.  Reserve 128K of
label space by default so we have the capability of making allocation
decisions persistent.  This reservation is not something we can add
later since it would result in the default size of a device-dax range
changing between kernel versions.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Device DAX is the device-centric analogue of Filesystem DAX
(CONFIG_FS_DAX).  It allows persistent memory ranges to be allocated and
mapped without need of an intervening file system.  This initial
infrastructure arranges for a libnvdimm pfn-device to be represented as
a different device-type so that it can be attached to a driver other
than the pmem driver.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The 'host' variable can be killed as it is always the same as the passed
in device.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The devm conversion obviates the need to continue to remember the queue
and disk locally in the driver.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Now that pmem internals have been disentangled from pfn setup, that code
can move to the core.  This is in preparation for adding another user of
the pfn-device capabilities.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

In preparation for providing an alternative (to block device) access
mechanism to persistent memory, convert pmem_rw_bytes() to
nsio_rw_bytes().  This allows ->rw_bytes() functionality without
requiring a 'struct pmem_device' to be instantiated.

In other words, when ->rw_bytes() is in use i/o is driven through
'struct nd_namespace_io', otherwise it is driven through 'struct
pmem_device' and the block layer.  This consolidates the disjoint calls
to devm_exit_badblocks() and devm_memunmap() into a common
devm_nsio_disable() and cleans up the init path to use a unified
pmem_attach_disk() implementation.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The leading '0x' in front of %pa is redundant, also we can just use %pR
to simplify the print statement.  The request parameters can be directly
taken from the resource as well.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Register a callback to clean up the request_queue and put the gendisk at
driver disable time.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Consolidate the information for issuing i/o to a blk-namespace, and
eliminate some pointer chasing.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

I/O errors events have the potential to be a high frequency and a log
message for each event can swamp the system.  This message is also
redundant with upper layer error reporting.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Save a pointer chase by storing the driver private data in the
request_queue rather than the gendisk.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Save a pointer chase by storing the driver private data in the
request_queue rather than the gendisk.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Register a callback to clean up the request_queue and put the gendisk at
driver disable time.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pass the device performing the probe so we can use a devm allocation for
the btt superblock.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pass the device performing the probe so we can use a devm allocation for
the pfn superblock.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

We can derive the common namespace from other information.  We also do
not need to cache it because all the usages are in slow paths.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pull device mapper fix from Mike Snitzer:
 "Fix for earlier 4.6-rc4 stable@ commit that introduced improper use of
  write lock in cmd_read_lock() -- due to cut-n-paste gone awry (and
  sparse didn't catch it)"

* tag 'dm-4.6-fix-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache metadata: fix cmd_read_lock() acquiring write lock

Commit 9567366f ("dm cache metadata: fix READ_LOCK macros and
cleanup WRITE_LOCK macros") uses down_write() instead of down_read() in
cmd_read_lock(), yet up_read() is used to release the lock in
READ_UNLOCK().  Fix it.

Fixes: 9567366f ("dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmed Samy <f.fallen45@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Pull char/misc fixes from Greg KH:
 "Here are some small char/misc driver fixes for 4.6-rc4.  Full details
  are in the shortlog, nothing major here.

  These have all been in linux-next for a while with no reported issues"

* tag 'char-misc-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  lkdtm: do not leak free page on kmalloc failure
  lkdtm: fix memory leak of base
  lkdtm: fix memory leak of val
  extcon: palmas: Drop stray IRQF_EARLY_RESUME flag

Pull misc fixes from Greg KH:
 "Here are three small fixes for 4.6-rc4.

  Two fix up some lz4 issues with big endian systems, and the remaining
  one resolves a minor debugfs issue that was reported.

  All have been in linux-next with no reported issues"

* tag 'driver-core-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  lib: lz4: cleanup unaligned access efficiency detection
  lib: lz4: fixed zram with lz4 on big endian machines
  debugfs: Make automount point inodes permanently empty

Pull USB driver fixes from Greg KH:
 "Here are some small USB fixes for 4.6-rc4.

  Mostly xhci fixes for reported issues, a UAS bug that has hit a number
  of people, including stable tree users, and a few other minor things.

  All have been in linux-next for a while with no reported issues"

* tag 'usb-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: hcd: out of bounds access in for_each_companion
  USB: uas: Add a new NO_REPORT_LUNS quirk
  USB: uas: Limit qdepth at the scsi-host level
  doc: usb: Fix typo in gadget_multi documentation
  usb: host: xhci-plat: Make enum xhci_plat_type start at a non zero value
  xhci: fix 10 second timeout on removal of PCI hotpluggable xhci controllers
  usb: xhci: fix wild pointers in xhci_mem_cleanup
  usb: host: xhci-plat: fix cannot work if R-Car Gen2/3 run on above 4GB phys
  usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT
  xhci: resume USB 3 roothub first
  usb: xhci: applying XHCI_PME_STUCK_QUIRK to Intel BXT B0 host
  cdc-acm: fix crash if flushed with nothing buffered

Pull dmaengine fixes from Vinod Koul:
 "This time we have some odd fixes in hsu, edma, omap and xilinx.

  Usual fixes and nothing special"

* tag 'dmaengine-fix-4.6-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: dw: fix master selection
  dmaengine: edma: special case slot limit workaround
  dmaengine: edma: Remove dynamic TPTC power management feature
  dmaengine: vdma: don't crash when bad channel is requested
  dmaengine: omap-dma: Do not suppress interrupts for memcpy
  dmaengine: omap-dma: Fix polled channel completion detection and handling
  dmaengine: hsu: correct use of channel status register
  dmaengine: hsu: correct residue calculation of active descriptor
  dmaengine: hsu: set HSU_CH_MTSR to memory width

Pull locking fixlet from Ingo Molnar:
 "Fixes a build warning on certain Kconfig combinations"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix print_collision() unused warning

Pull EFI fix from Ingo Molnar:
 "An arm64 boot crash fix"

* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/arm64: Don't apply MEMBLOCK_NOMAP to UEFI memory map mapping

Pull block fixes from Jens Axboe:
 "A few fixes for the current series. This contains:

   - Two fixes for NVMe:

     One fixes a reset race that can be triggered by repeated
     insert/removal of the module.

     The other fixes an issue on some platforms, where we get probe
     timeouts since legacy interrupts isn't working.  This used not to
     be a problem since we had the worker thread poll for completions,
     but since that was killed off, it means those poor souls can't
     successfully probe their NVMe device.  Use a proper IRQ check and
     probe (msi-x -> msi ->legacy), like most other drivers to work
     around this.  Both from Keith.

   - A loop corruption issue with offset in iters, from Ming Lei.

   - A fix for not having the partition stat per cpu ref count
     initialized before sending out the KOBJ_ADD, which could cause user
     space to access the counter prior to initialization.  Also from
     Ming Lei.

   - A fix for using the wrong congestion state, from Kaixu Xia"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: loop: fix filesystem corruption in case of aio/dio
  NVMe: Always use MSI/MSI-x interrupts
  NVMe: Fix reset/remove race
  writeback: fix the wrong congested state variable definition
  block: partition: initialize percpuref before sending out KOBJ_ADD

Pull libnvdimm fixes from Ross Zwisler:
 "Two fixes:

   - Fix memcpy_from_pmem() to fallback to memcpy() for architectures
     where CONFIG_ARCH_HAS_PMEM_API=n.

   - Add a comment explaining why we write data twice when clearing
     poison in pmem_do_bvec().

  This has passed a boot test on an X86_32 config, which was the
  architecture where issue #1 above was first noticed"

Dan Williams adds:
 "We're giving this multi-maintainer setup a shot, so expect libnvdimm
  pull requests from either Ross or I going forward"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, pmem: clarify the write+clear_poison+write flow
  pmem: fix BUG() error in pmem.h:48 on X86_32

Pull MTD fix from Brian Norris:
 "One MTD fix for v4.6-rc4:

  In the v4.4 cycle, we relaxed the requirement for assigning
  mtd->owner, but we didn't remove this error case.  It's hit only
  by drivers that are both:

   (a) using nand_scan() directly
  and
   (b) built as modules

  We haven't seen explicit complaints about this (most use cases don't
  fit one or both of the above), but we should definitely not be
  BUG()'ing here"

* tag 'for-linus-20160415' of git://git.infradead.org/linux-mtd:
  mtd: nand: Drop mtd.owner requirement in nand_scan