[GIT PULL] XArray updates

[Matthew Wilcox]

Hi Linus,

We found some bugs in the DAX conversion to XArray (and one bug which
predated the XArray conversion).  There were a couple of bugs in some of
the higher-level functions, which aren't actually being called in today's
kernel, but surfaced as a result of converting existing radix tree &
IDR users over to the XArray.  Some of the other changes to how the
higher-level APIs work were also motivated by converting various users;
again, they're not in use in today's kernel, so changing them has a low
probability of introducing a bug.

Dan can still trigger a bug in the DAX code with hot-offline/online,
and we're working on tracking that down.

The following changes since commit 651022382c7f8da46cb4872a545ee1da6d097d2a:

  Linux 4.20-rc1 (2018-11-04 15:37:52 -0800)

are available in the Git repository at:

  git://git.infradead.org/users/willy/linux-dax.git xarray

for you to fetch changes up to fffc9a260e38acec3187515738122a3ecb24ac90:

  XArray tests: Add missing locking (2018-11-19 09:41:11 -0500)

----------------------------------------------------------------
Matthew Wilcox (19):
      XArray: Fix xa_for_each with a single element at 0
      XArray: Export __xa_foo to non-GPL modules
      nilfs2: Use xa_erase_irq
      XArray: Regularise xa_reserve
      XArray: Unify xa_cmpxchg and __xa_cmpxchg
      XArray: Turn xa_erase into an exported function
      XArray: Add xa_store_bh() and xa_store_irq()
      XArray: Unify xa_store and __xa_store
      XArray: Handle NULL pointers differently for allocation
      XArray: Fix Documentation
      XArray: Correct xa_store_range
      XArray tests: Correct some 64-bit assumptions
      dax: Remove optimisation from dax_lock_mapping_entry
      dax: Make sure the unlocking entry isn't locked
      dax: Reinstate RCU protection of inode
      dax: Fix dax_unlock_mapping_entry for PMD pages
      dax: Fix huge page faults
      dax: Avoid losing wakeup in dax_lock_mapping_entry
      XArray tests: Add missing locking

 Documentation/core-api/xarray.rst |  52 ++++++--
 fs/dax.c                          |  60 +++++----
 fs/nilfs2/btnode.c                |   4 +-
 include/linux/xarray.h            | 267 +++++++++++++++++++++++++++++---------
 lib/test_xarray.c                 |  50 ++++++-
 lib/xarray.c                      | 139 +++++++++-----------
 6 files changed, 387 insertions(+), 185 deletions(-)