Core block IO changes for 4.7-rc1

Hi Linus,

This is the core block IO changes for this merge window. Nothing earth shattering in here, it's mostly just fixes. In detail:

- Fix for a long standing issue where wrong ordering in blk-mq caused order_to_size() to spew a warning. From Bart.

- Async discard support from Christoph. Basically just splitting our sync interface into a submit + wait part.

- Add a cleaner interface for flagging whether a device has a write back cache or not. We've previously overloaded blk_queue_flush() with this, but let's make it more explicit. Drivers cleaned up and updated in the drivers pull request. From me.

- Fix for a double check for whether IO accounting is enabled or not. From Michael Callahan.

- Fix for the async discard from Mike Snitzer, reinstating the early EOPNOTSUPP return if the device doesn't support discards.

- Also from Mike, export bio_inc_remaining() so dm can drop it's private copy of it.

- From Ming Lin, add support for passing in an offset for request payloads.

- Tag function export from Sagi, which will be used in NVMe in the drivers pull.

- Two blktrace related fixes from Shaohua.

- Propagate NOMERGE flag when making a request from a bio, also from Shaohua.

- An optimization to not parse cgroup paths in blk-throttle, if we don't need to. From Shaohua.

Please pull!

git://git.kernel.dk/linux-block.git for-4.7/core

----------------------------------------------------------------
Bartlomiej Zolnierkiewicz (1):
blk-mq: fix undefined behaviour in order_to_size()

Christoph Hellwig (2):
block: remove struct bio_batch
block: add __blkdev_issue_discard

Jens Axboe (1):
block: add ability to flag write back caching on a device

Michael Callahan (1):
block: Minor blk_account_io_start usage cleanup

Mike Snitzer (2):
block: reinstate early return of -EOPNOTSUPP from blkdev_issue_discard
block: make bio_inc_remaining() interface accessible again

Ming Lin (1):
block: add offset in blk_add_request_payload()

Sagi Grimberg (1):
blk-mq: Export tagset iter function

Shaohua Li (4):
block: copy NOMERGE flag from bio to request
blktrace: delete garbage for message trace
blktrace: add missed mask name
blk-throttle: don't parse cgroup path if trace isn't enabled

 Documentation/block/queue-sysfs.txt |   9 ++
 block/bio.c                         |  11 ---
 block/blk-core.c                    |   5 +-
 block/blk-lib.c                     | 178 +++++++++++++-----------------------
 block/blk-mq-tag.c                  |  12 +++
 block/blk-mq.c                      |   5 +-
 block/blk-settings.c                |  26 ++++++
 block/blk-sysfs.c                   |  39 ++++++++
 block/blk-throttle.c                |   5 +-
 drivers/block/skd_main.c            |   2 +-
 drivers/scsi/sd.c                   |   2 +-
 include/linux/bio.h                 |  11 +++
 include/linux/blk-mq.h              |   2 +
 include/linux/blk_types.h           |   2 +-
 include/linux/blkdev.h              |   7 +-
 include/linux/blktrace_api.h        |   9 ++
 kernel/trace/blktrace.c             |   2 +
 17 files changed, 190 insertions(+), 137 deletions(-)

Jens Axboe