Pull block fixes from Jens Axboe:
 "Final round of fixes for this merge window - some of this has come up
  after the initial pull request, and some of it was put in a post-merge
  branch before the merge window.

  This contains:

   - Fix for a bad check for an error on dma mapping in the mtip32xx
     driver, from Alexey Khoroshilov.

   - A set of fixes for lightnvm, from Javier, Matias, and Wenwei.

   - An NVMe completion record corruption fix from Marta, ensuring that
     we read things in the right order.

   - Two writeback fixes from Tejun, marked for stable@ as well.

   - A blk-mq sw queue iterator fix from Thomas, fixing an oops for
     sparse CPU maps.  They hit this in the hot plug/unplug rework"

* 'for-linus' of git://git.kernel.dk/linux-block:
  nvme: avoid cqe corruption when update at the same time as read
  writeback, cgroup: fix use of the wrong bdi_writeback which mismatches the inode
  writeback, cgroup: fix premature wb_put() in locked_inode_to_wb_and_lock_list()
  blk-mq: Use proper cpumask iterator
  mtip32xx: fix checks for dma mapping errors
  lightnvm: do not load L2P table if not supported
  lightnvm: do not reserve lun on l2p loading
  nvme: lightnvm: return ppa completion status
  lightnvm: add a bitmap of luns
  lightnvm: specify target's logical address area
  null_blk: add lightnvm null_blk device to the nullb_list

queue_for_each_ctx() iterates over per_cpu variables under the assumption that
the possible cpu mask cannot have holes. That's wrong as all cpumasks can have
holes. In case there are holes the iteration ends up accessing uninitialized
memory and crashing as a result.

Replace the macro by a proper for_each_possible_cpu() loop and drop the unused
macro blk_ctx_sum() which references queue_for_each_ctx().

Reported-by: Xiong Zhou <jencce.kernel@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Pull libata updates from Tejun Heo:

 - ahci grew runtime power management support so that the controller can
   be turned off if no devices are attached.

 - sata_via isn't dead yet.  It got hotplug support and more refined
   workaround for certain WD drives.

 - Misc cleanups.  There's a merge from for-4.5-fixes to avoid confusing
   conflicts in ahci PCI ID table.

* 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  ata: ahci_xgene: dereferencing uninitialized pointer in probe
  AHCI: Remove obsolete Intel Lewisburg SATA RAID device IDs
  ata: sata_rcar: Use ARCH_RENESAS
  sata_via: Implement hotplug for VT6421
  sata_via: Apply WD workaround only when needed on VT6421
  ahci: Add runtime PM support for the host controller
  ahci: Add functions to manage runtime PM of AHCI ports
  ahci: Convert driver to use modern PM hooks
  ahci: Cache host controller version
  scsi: Drop runtime PM usage count after host is added
  scsi: Set request queue runtime PM status back to active on resume
  block: Add blk_set_runtime_active()
  ata: ahci_mvebu: add support for Armada 3700 variant
  libata: fix unbalanced spin_lock_irqsave/spin_unlock_irq() in ata_scsi_park_show()
  libata: support AHCI on OCTEON platform

Pull core block updates from Jens Axboe:
 "Here are the core block changes for this merge window.  Not a lot of
  exciting stuff going on in this round, most of the changes have been
  on the driver side of things.  That pull request is coming next.  This
  pull request contains:

   - A set of fixes for chained bio handling from Christoph.

   - A tag bounds check for blk-mq from Hannes, ensuring that we don't
     do something stupid if a device reports an invalid tag value.

   - A set of fixes/updates for the CFQ IO scheduler from Jan Kara.

   - A set of blk-mq fixes from Keith, adding support for dynamic
     hardware queues, and fixing init of max_dev_sectors for stacking
     devices.

   - A fix for the dynamic hw context from Ming.

   - Enabling of cgroup writeback support on a block device, from
     Shaohua"

* 'for-4.6/core' of git://git.kernel.dk/linux-block:
  blk-mq: add bounds check on tag-to-rq conversion
  block: bio_remaining_done() isn't unlikely
  block: cleanup bio_endio
  block: factor out chained bio completion
  block: don't unecessarily clobber bi_error for chained bios
  block-dev: enable writeback cgroup support
  blk-mq: Fix NULL pointer updating nr_requests
  blk-mq: mark request queue as mq asap
  block: Initialize max_dev_sectors to 0
  blk-mq: dynamic h/w context count
  cfq-iosched: Allow parent cgroup to preempt its child
  cfq-iosched: Allow sync noidle workloads to preempt each other
  cfq-iosched: Reorder checks in cfq_should_preempt()
  cfq-iosched: Don't group_idle if cfqq has big thinktime

Pull device mapper updates from Mike Snitzer:

 - Most attention this cycle went to optimizing blk-mq request-based DM
   (dm-mq) that is used exclussively by DM multipath:

     - A stable fix for dm-mq that eliminates excessive context
       switching offers the biggest performance improvement (for both
       IOPs and throughput).

     - But more work is needed, during the next cycle, to reduce
       spinlock contention in DM multipath on large NUMA systems.

 - A stable fix for a NULL pointer seen when DM stats is enabled on a DM
   multipath device that must requeue an IO due to path failure.

 - A stable fix for DM snapshot to disallow the COW and origin devices
   from being identical.  This amounts to graceful failure in the face
   of userspace error because these devices shouldn't ever be identical.

 - Stable fixes for DM cache and DM thin provisioning to address crashes
   seen if/when their respective metadata device experiences failures
   that cause the transition to 'fail_io' mode.

 - The DM cache 'mq' policy is now an alias for the 'smq' policy.  The
   'smq' policy proved to be consistently better than 'mq'.  As such
   'mq', with all its complex user-facing tunables, has been eliminated.

 - Improve DM thin provisioning to consistently return -ENOSPC once the
   thin-pool's data volume is out of space.

 - Improve DM core to properly handle error propagation if
   bio_integrity_clone() fails in clone_bio().

 - Other small cleanups and improvements to DM core.

* tag 'dm-4.6-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (41 commits)
  dm: fix rq_end_stats() NULL pointer in dm_requeue_original_request()
  dm thin: consistently return -ENOSPC if pool has run out of data space
  dm cache: bump the target version
  dm cache: make sure every metadata function checks fail_io
  dm: add missing newline between DM_DEBUG_BLOCK_STACK_TRACING and DM_BUFIO
  dm cache policy smq: clarify that mq registration failure was for 'mq'
  dm: return error if bio_integrity_clone() fails in clone_bio()
  dm thin metadata: don't issue prefetches if a transaction abort has failed
  dm snapshot: disallow the COW and origin devices from being identical
  dm cache: make the 'mq' policy an alias for 'smq'
  dm: drop unnecessary assignment of md->queue
  dm: reorder 'struct mapped_device' members to fix alignment and holes
  dm: remove dummy definition of 'struct dm_table'
  dm: add 'dm_numa_node' module parameter
  dm thin metadata: remove needless newline from subtree_dec() DMERR message
  dm mpath: cleanup reinstate_path() et al based on code review
  dm mpath: remove __pgpath_busy forward declaration, rename to pgpath_busy
  dm mpath: switch from 'unsigned' to 'bool' for flags where appropriate
  dm round robin: use percpu 'repeat_count' and 'current_path'
  dm path selector: remove 'repeat_count' return from .select_path hook
  ...

This patch has been carried in the Android tree for quite some time and
is one of the few patches required to get a mainline kernel up and
running with an exsiting Android userspace.  So I wanted to submit it
for review and consideration if it should be merged.

For partitions, add new uevent parameters 'PARTN' which specifies the
partitions index in the table, and 'PARTNAME', which specifies PARTNAME
specifices the partition name of a partition device.

Android's userspace uses this for creating device node links from the
partition name and number, ie:

    /dev/block/platform/soc/by-name/system
or
    /dev/block/platform/soc/by-num/p1

One can see its usage here:
    https://android.googlesource.com/platform/system/core/+/master/init/devices.cpp#355
and
    https://android.googlesource.com/platform/system/core/+/master/init/devices.cpp#494

[john.stultz@linaro.org: dropped NPARTS and reworded commit message for context]
Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: <harald@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We need to check for a valid index before accessing the array
element to avoid accessing invalid memory regions.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>

Modified by Jens to drop the unlikely(), and make the fall through
path be having a valid tag.

Signed-off-by: Jens Axboe <axboe@fb.com>

We use bio chaining during most I/Os these days due to the delayed
bio splitting.  Additionally XFS will start using it, and there is
a pending direct I/O rewrite also making heavy use for it.  Don't
pretend it's always unlikely, and let the branch predictor do it's
job instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Replace the while loop that unecessarily checks for a NULL bio in the fast
path with a simple goto loop.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Factor common code between bio_chain_endio and bio_endio into a common
helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>