block: Switch from BFQ-v7r2 for 3.12.0 to BFQ-v7r3 for 3.12.0

. IMPROVEMENT: Improved throughput boosting with NCQ-capable HDDs and
  random workloads. The mechanism that further boosts throghput with
  these devices and workloads is activated only in the cases where it
  does not cause any violation of throughput-distribution and latency
  guarantees.
. IMPROVEMENT: Generalized the computation of the parameters of the
  low-latency heuristic for interactive applications, so as to fit also
  slower storage devices. The purpose of this improvement is to preserve
  low-latency guarantees for interactive applications also on slower
  devices, such as portable hard disks, multimedia and SD cards.
. BUGFIX: Re-added MODULE_LICENSE macro.
. CODE IMPROVEMENTS: Small code cleanups; introduced a coherent naming
  scheme for all identifiers related to weight raising; refactored and
  optimized a few hot paths.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Reported-by: Mikhail Akushsky <namelles.one@gmail.com>
block: Switch from BFQ-v7r3 for 3.12.0 to BFQ-v7r4 for 3.12.0

. BUGFIX. Modified the code so as to be robust against late detection of
  NCQ support for a rotational device.
. BUGFIX. Removed a bug that hindered the correct throughput distribution
  on flash-based devices when not every process had to receive the same
  fraction of the throughput. This fix entailed also a little efficiency
  improvement, because it implied the removal of a short function executed
  in a hot path.
. CODESTYLE IMPROVEMENT: removed quoted strings split across lines.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Reported-by: Steven Barrett <damentz@gmail.com>
Reported-by: Claire Farron <diesal3@googlemail.com>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
block: Switch from BFQ-v7r4 for 3.12.0 to BFQ-v7r5 for 3.12.0

. IMPROVEMENT: Improve throughput boosting by idling the device
  only for processes that, in addition to perform sequential I/O,
  are I/O-bound (apart from weight-raised queues, for which idling
  is always performed to guarantee them a low latency).
. IMPROVEMENT: Improve throughput boosting by depriving processes
  that cooperate often of weight-raising.
. CODE IMPROVEMENT: Pass of improvement of the readability of both
  comments and actual code.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Tested-by: Takashi Iwai <tiwai@suse.de>
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
block: Switch from BFQ-v7r5 for 3.12.0 to BFQ-v7r6 for 3.12.0

. IMPROVEMENT: Introduced a new mechanism that helps get the job done
  more quickly for services and applications that create or reactivate
  many parallel I/O-bound processes. Examples are systemd at boot, or
  commands such as git grep.
. CODE IMPROVEMENTS: Small code cleanups and improvements.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
block: Switch from BFQ-v7r6 for 3.12.0 to BFQ-v7r7 for 3.12.0

. BUGFIX: Prevent the OOM queue from being involved in the queue
  cooperation mechanism. In fact, since the requests temporarily
  redirected to the OOM queue could be redirected again to dedicated
  queues at any time, the state needed to correctly handle merging
  with the OOM queue would be quite complex and expensive to
  maintain. Besides, in such a critical condition as an out of
  memory, the benefits of queue merging may be little relevant, or
  even negligible.

. IMPROVEMENT: Let the OOM queue be initialized only once. Previously,
  the OOM queue was reinitialized, at each request enqueue, with the
  parameters related to the process that issued that request.
  Depending on the parameters of the processes doing I/O, this could
  easily cause the OOM queue to be moved continuously across service
  trees, or even across groups. It also caused the parameters of the
  OOM queue to be continuously reset in any case.

. CODE IMPROVEMENT. Performed some minor code cleanups, and added some
  BUG_ON()s that, if the weight of an entity becomes inconsistent,
  should better help understand why.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Reported-by: Hector Martin <hector@marcansoft.com>
EXTRAVERSION updated