block: Add support for reinsert a dispatched req

Add support for reinserting a dispatched request back to the
scheduler's internal data structures.
This capability is used by the device driver when it chooses to
interrupt the current request transmission and execute another (more
urgent) pending request. For example: interrupting long write in order
to handle pending read. The device driver re-inserts the
remaining write request back to the scheduler, to be rescheduled
for transmission later on.

Add API for verifying whether the current scheduler
supports reinserting requests mechanism. If reinsert mechanism isn't
supported by the scheduler, this code path will never be activated.

Change-Id: I5c982a66b651ebf544aae60063ac8a340d79e67f
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:

	include/linux/elevator.h
block: Add API for urgent request handling

This patch add support in block & elevator layers for handling
urgent requests. The decision if a request is urgent or not is taken
by the scheduler. Urgent request notification is passed to the underlying
block device driver (eMMC for example). Block device driver may decide to
interrupt the currently running low priority request to serve the new
urgent request. By doing so READ latency is greatly reduced in read&write
collision scenarios.

Note that if the current scheduler doesn't implement the urgent request
mechanism, this code path is never activated.

Change-Id: I8aa74b9b45c0d3a2221bd4e82ea76eb4103e7cfa
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Fix build error with block *
(block/elevator.c: In function ‘elv_reinsert_request’:
block/elevator.c:623:18: error: ‘struct elevator_queue’ has no member named ‘type’
block/elevator.c:626:19: error: ‘struct elevator_queue’ has no member named ‘type’

block/blk-core.c: In function ‘__blk_run_queue’:
block/blk-core.c:312:14: error: ‘struct elevator_queue’ has no member named ‘type’
block/blk-core.c:314:14: error: ‘struct elevator_queue’ has no member named ‘type’
block/blk-core.c: In function ‘blk_reinsert_req_sup’:
block/blk-core.c:985:20: error: ‘struct elevator_queue’ has no member named ‘type’
block/blk-core.c:986:1: warning: control reaches end of non-void function [-Wreturn-type])
ROW: Update the latest ROW Scheduler
(block: ROW: Correct minimum values of ROW tunable parameters
block: ROW: Fix forced dispatch
row: Adding support for reinsert already dispatched req
block:row: fix idling mechanism in ROW
row: Add support for urgent request handling
block: row: Add some debug information on ROW queues
block: row: Insert dispatch_quantum into struct row_queue
block: row: fix sysfs functions - idle_time conversion
block: row: Aggregate row_queue parameters to one structure)