linux.git/block, branch v4.19-rc2

block: bsg: move atomic_t ref_count variable to refcount API

2018-08-28T01:17:02+00:00

Currently, variable ref_count within the bsg_device struct is of
type atomic_t.  For variables being used as reference counters,
the refcount API should be used instead of atomic.  The newer
refcount API works to prevent counter overflows and use-after-free
bugs.  So, move this varable from the atomic API to refcount,
potentially avoiding the issues mentioned.

Signed-off-by: John Pittman 
Signed-off-by: Jens Axboe

block: remove unnecessary condition check

2018-08-28T01:16:06+00:00

kmem_cache_destroy() can handle NULL pointer correctly, so there is
no need to check e->icq_cache before calling kmem_cache_destroy().

Signed-off-by: Chengguang Xu 
Signed-off-by: Jens Axboe

blk-wbt: remove dead code

2018-08-27T19:32:12+00:00

We already note and mark discard and swap IO from bio_to_wbt_flags().

Signed-off-by: Jens Axboe

blk-wbt: improve waking of tasks

2018-08-27T17:27:26+00:00

We have two potential issues:

1) After commit 2887e41b910b, we only wake one process at the time when
   we finish an IO. We really want to wake up as many tasks as can
   queue IO. Before this commit, we woke up everyone, which could cause
   a thundering herd issue.

2) A task can potentially consume two wakeups, causing us to (in
   practice) miss a wakeup.

Fix both by providing our own wakeup function, which stops
__wake_up_common() from waking up more tasks if we fail to get a
queueing token. With the strict ordering we have on the wait list, this
wakes the right tasks and the right amount of tasks.

Based on a patch from Jianchao Wang .

Tested-by: Agarwal, Anchal 
Signed-off-by: Jens Axboe

blk-wbt: abstract out end IO completion handler

2018-08-27T17:27:24+00:00

Prep patch for calling the handler from a different context,
no functional changes in this patch.

Tested-by: Agarwal, Anchal 
Signed-off-by: Jens Axboe

blk-wbt: don't maintain inflight counts if disabled

2018-08-23T15:34:46+00:00

A previous commit removed the ability to have per-rq flags. We used
those flags to maintain inflight counts. Since we don't have those
anymore, we have to always maintain inflight counts, even if wbt is
disabled. This is clearly suboptimal.

Add a queue quiesce around changing the wbt latency settings from sysfs
to work around this. With that, we can reliably put the enabled check in
our bio_to_wbt_flags(), since we know the WBT_TRACKED flag will be
consistent for the lifetime of the request.

Fixes: c1c80384c8f ("block: remove external dependency on wbt_flags")
Reviewed-by: Josef Bacik 
Signed-off-by: Jens Axboe

blk-wbt: fix has-sleeper queueing check

2018-08-22T21:07:32+00:00

We need to do this inside the loop as well, or we can allow new
IO to supersede previous IO.

Tested-by: Anchal Agarwal 
Signed-off-by: Jens Axboe

blk-wbt: use wq_has_sleeper() for wq active check

2018-08-22T21:07:31+00:00

We need the memory barrier before checking the list head,
use the appropriate helper for this. The matching queue
side memory barrier is provided by set_current_state().

Tested-by: Anchal Agarwal 
Signed-off-by: Jens Axboe

blk-wbt: move disable check into get_limit()

2018-08-22T21:07:31+00:00

Check it in one place, instead of in multiple places.

Tested-by: Anchal Agarwal 
Signed-off-by: Jens Axboe

Merge tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block

2018-08-22T20:38:05+00:00

Pull more block updates from Jens Axboe:

 - Set of bcache fixes and changes (Coly)

 - The flush warn fix (me)

 - Small series of BFQ fixes (Paolo)

 - wbt hang fix (Ming)

 - blktrace fix (Steven)

 - blk-mq hardware queue count update fix (Jianchao)

 - Various little fixes

* tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block: (31 commits)
  block/DAC960.c: make some arrays static const, shrinks object size
  blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter
  blk-mq: init hctx sched after update ctx and hctx mapping
  block: remove duplicate initialization
  tracing/blktrace: Fix to allow setting same value
  pktcdvd: fix setting of 'ret' error return for a few cases
  block: change return type to bool
  block, bfq: return nbytes and not zero from struct cftype .write() method
  block, bfq: improve code of bfq_bfqq_charge_time
  block, bfq: reduce write overcharge
  block, bfq: always update the budget of an entity when needed
  block, bfq: readd missing reset of parent-entity service
  blk-wbt: fix IO hang in wbt_wait()
  block: don't warn for flush on read-only device
  bcache: add the missing comments for smp_mb()/smp_wmb()
  bcache: remove unnecessary space before ioctl function pointer arguments
  bcache: add missing SPDX header
  bcache: move open brace at end of function definitions to next line
  bcache: add static const prefix to char * array declarations
  bcache: fix code comments style
  ...