linux-stable.git/block, branch v4.19.2

block, bfq: correctly charge and reset entity service in all cases

2018-11-13T19:08:28+00:00

[ Upstream commit cbeb869a3d1110450186b738199963c5e68c2a71 ]

BFQ schedules entities (which represent either per-process queues or
groups of queues) as a function of their timestamps. In particular, as
a function of their (virtual) finish times. The finish time of an
entity is computed as a function of the budget assigned to the entity,
assuming, tentatively, that the entity, once in service, will receive
an amount of service equal to its budget. Then, when the entity is
expired because it finishes to be served, this finish time is updated
as a function of the actual service received by the entity. This
allows the entity to be correctly charged with only the service
received, and then to be correctly re-scheduled.

Yet an entity may receive service also while not being the entity in
service (in the scheduling environment of its parent entity), for
several reasons. If the entity remains with no backlog while receiving
this 'unofficial' service, then it is expired. Also on such an
expiration, the finish time of the entity should be updated to account
for only the service actually received by the entity. Unfortunately,
such an update is not performed for an entity expiring without being
the entity in service.

In a similar vein, the service counter of the entity in service is
reset when the entity is expired, to be ready to be used for next
service cycle. This reset too should be performed also in case an
entity is expired because it remains empty after receiving service
while not being the entity in service. But in this case the reset is
not performed.

This commit performs the above update of the finish time and reset of
the service received, also for an entity expiring while not being the
entity in service.

Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

block: make sure writesame bio is aligned with logical block size

2018-11-13T19:08:16+00:00

commit 34ffec60b27aa81d04e274e71e4c6ef740f75fc7 upstream.

Obviously the created writesame bio has to be aligned with logical block
size, and use bio_allowed_max_sectors() to retrieve this number.

Cc: stable@vger.kernel.org
Cc: Mike Snitzer 
Cc: Christoph Hellwig 
Cc: Xiao Ni 
Cc: Mariusz Dabrowski 
Fixes: b49a0871be31a745b2ef ("block: remove split code in blkdev_issue_{discard,write_same}")
Tested-by: Rui Salvaterra 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: make sure discard bio is aligned with logical block size

2018-11-13T19:08:16+00:00

commit 1adfc5e4136f5967d591c399aff95b3b035f16b7 upstream.

Obviously the created discard bio has to be aligned with logical block size.

This patch introduces the helper of bio_allowed_max_sectors() for
this purpose.

Cc: stable@vger.kernel.org
Cc: Mike Snitzer 
Cc: Christoph Hellwig 
Cc: Xiao Ni 
Cc: Mariusz Dabrowski 
Fixes: 744889b7cbb56a6 ("block: don't deal with discard limit in blkdev_issue_discard()")
Fixes: a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks")
Reported-by: Rui Salvaterra 
Tested-by: Rui Salvaterra 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: setup bounce bio_sets properly

2018-11-13T19:08:16+00:00

commit 52990a5fb0c991ecafebdab43138b5ed41376852 upstream.

We're only setting up the bounce bio sets if we happen
to need bouncing for regular HIGHMEM, not if we only need
it for ISA devices.

Protect the ISA bounce setup with a mutex, since it's
being invoked from driver init functions and can thus be
called in parallel.

Cc: stable@vger.kernel.org
Reported-by: Ondrej Zary 
Tested-by: Ondrej Zary 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: don't deal with discard limit in blkdev_issue_discard()

2018-10-18T13:23:40+00:00

blk_queue_split() does respect this limit via bio splitting, so no
need to do that in blkdev_issue_discard(), then we can align to
normal bio submit(bio_add_page() & submit_bio()).

More importantly, this patch fixes one issue introduced in a22c4d7e34402cc
("block: re-add discard_granularity and alignment checks"), in which
zero discard bio may be generated in case of zero alignment.

Fixes: a22c4d7e34402ccdf3 ("block: re-add discard_granularity and alignment checks")
Cc: stable@vger.kernel.org
Cc: Ming Lin 
Cc: Mike Snitzer 
Cc: Christoph Hellwig 
Cc: Xiao Ni 
Tested-by: Mariusz Dabrowski 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-wbt: wake up all when we scale up, not down

2018-10-11T19:31:28+00:00

Tetsuo brought to my attention that I screwed up the scale_up/scale_down
helpers when I factored out the rq-qos code.  We need to wake up all the
waiters when we add slots for requests to make, not when we shrink the
slots.  Otherwise we'll end up things waiting forever.  This was a
mistake and simply puts everything back the way it was.

cc: stable@vger.kernel.org
Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
eported-by: Tetsuo Handa 
Signed-off-by: Josef Bacik 
Signed-off-by: Jens Axboe

blk-mq: I/O and timer unplugs are inverted in blktrace

2018-09-27T19:12:44+00:00

trace_block_unplug() takes true for explicit unplugs and false for
implicit unplugs.  schedule() unplugs are implicit and should be
reported as timer unplugs.  While correct in the legacy code, this has
been inverted in blk-mq since 4.11.

Cc: stable@vger.kernel.org
Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers")
Reviewed-by: Omar Sandoval 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Jens Axboe

block: fix deadline elevator drain for zoned block devices

2018-09-27T01:57:24+00:00

When the deadline scheduler is used with a zoned block device, writes
to a zone will be dispatched one at a time. This causes the warning
message:

deadline: forced dispatching is broken (nr_sorted=X), please report this

to be displayed when switching to another elevator with the legacy I/O
path while write requests to a zone are being retained in the scheduler
queue.

Prevent this message from being displayed when executing
elv_drain_elevator() for a zoned block device. __blk_drain_queue() will
loop until all writes are dispatched and completed, resulting in the
desired elevator queue drain without extensive modifications to the
deadline code itself to handle forced-dispatch calls.

Signed-off-by: Damien Le Moal 
Fixes: 8dc8146f9c92 ("deadline-iosched: Introduce zone locking support")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe

blk-mq: Allow blocking queue tag iter callbacks

2018-09-26T02:17:59+00:00

A recent commit runs tag iterator callbacks under the rcu read lock,
but existing callbacks do not satisfy the non-blocking requirement.
The commit intended to prevent an iterator from accessing a queue that's
being modified. This patch fixes the original issue by taking a queue
reference instead of reading it, which allows callbacks to make blocking
calls.

Fixes: f5bbbbe4d6357 ("blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter")
Acked-by: Jianchao Wang 
Signed-off-by: Keith Busch 
Signed-off-by: Jens Axboe

block: use nanosecond resolution for iostat

2018-09-22T02:26:59+00:00

Klaus Kusche reported that the I/O busy time in /proc/diskstats was not
updating properly on 4.18. This is because we started using ktime to
track elapsed time, and we convert nanoseconds to jiffies when we update
the partition counter. However, this gets rounded down, so any I/Os that
take less than a jiffy are not accounted for. Previously in this case,
the value of jiffies would sometimes increment while we were doing I/O,
so at least some I/Os were accounted for.

Let's convert the stats to use nanoseconds internally. We still report
milliseconds as before, now more accurately than ever. The value is
still truncated to 32 bits for backwards compatibility.

Fixes: 522a777566f5 ("block: consolidate struct request timestamp fields")
Cc: stable@vger.kernel.org
Reported-by: Klaus Kusche 
Signed-off-by: Omar Sandoval 
Signed-off-by: Jens Axboe