Pull block fixes from Jens Axboe:
 "Small collection of fixes that should go into this series. This pull
  contains:

   - NVMe pull request with three small fixes (via Christoph)

   - Kill useless NULL check before kmem_cache_destroy (Chengguang Xu)

   - Xen block driver pull request with persistent grant flushing fixes
     (Juergen Gross)

   - Final wbt fixes, wrapping up the changes for this series. These
     have been heavily tested (me)

   - cdrom info leak fix (Scott Bauer)

   - ATA dma quirk for SQ201 (Linus Walleij)

   - Straight forward bsg refcount_t conversion (John Pittman)"

* tag 'for-linus-20180830' of git://git.kernel.dk/linux-block:
  cdrom: Fix info leak/OOB read in cdrom_ioctl_drive_status
  nvmet: free workqueue object if module init fails
  nvme-fcloop: Fix dropped LS's to removed target port
  nvme-pci: add a memory barrier to nvme_dbbuf_update_and_check_event
  block: bsg: move atomic_t ref_count variable to refcount API
  block: remove unnecessary condition check
  ata: ftide010: Add a quirk for SQ201
  blk-wbt: remove dead code
  blk-wbt: improve waking of tasks
  blk-wbt: abstract out end IO completion handler
  xen/blkback: remove unused pers_gnts_lock from struct xen_blkif_ring
  xen/blkback: move persistent grants flags to bool
  xen/blkfront: reorder tests in xlblk_init()
  xen/blkfront: cleanup stale persistent grants
  xen/blkback: don't keep persistent grants too long

Pull Xen block driver fixes from Konrad:

"Fix for flushing out persistent pages at a deterministic rate"

* 'stable/for-jens-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/blkback: remove unused pers_gnts_lock from struct xen_blkif_ring
  xen/blkback: move persistent grants flags to bool
  xen/blkfront: reorder tests in xlblk_init()
  xen/blkfront: cleanup stale persistent grants
  xen/blkback: don't keep persistent grants too long

pers_gnts_lock isn't being used anywhere. Remove it.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The struct persistent_gnt flags member is meant to be a bitfield of
different flags. There is only PERSISTENT_GNT_ACTIVE flag left, so
convert it to a bool named "active".

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In case we don't want pv block devices we should not test parameters
for sanity and eventually print out error messages. So test precluding
conditions before checking parameters.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Add a periodic cleanup function to remove old persistent grants which
are no longer in use on the backend side. This avoids starvation in
case there are lots of persistent grants for a device which no longer
is involved in I/O business.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Persistent grants are allocated until a threshold per ring is being
reached. Those grants won't be freed until the ring is being destroyed
meaning there will be resources kept busy which might no longer be
used.

Instead of freeing only persistent grants until the threshold is
reached add a timestamp and remove all persistent grants not having
been in use for a minute.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Pull IDA updates from Matthew Wilcox:
 "A better IDA API:

      id = ida_alloc(ida, GFP_xxx);
      ida_free(ida, id);

  rather than the cumbersome ida_simple_get(), ida_simple_remove().

  The new IDA API is similar to ida_simple_get() but better named.  The
  internal restructuring of the IDA code removes the bitmap
  preallocation nonsense.

  I hope the net -200 lines of code is convincing"

* 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax: (29 commits)
  ida: Change ida_get_new_above to return the id
  ida: Remove old API
  test_ida: check_ida_destroy and check_ida_alloc
  test_ida: Convert check_ida_conv to new API
  test_ida: Move ida_check_max
  test_ida: Move ida_check_leaf
  idr-test: Convert ida_check_nomem to new API
  ida: Start new test_ida module
  target/iscsi: Allocate session IDs from an IDA
  iscsi target: fix session creation failure handling
  drm/vmwgfx: Convert to new IDA API
  dmaengine: Convert to new IDA API
  ppc: Convert vas ID allocation to new IDA API
  media: Convert entity ID allocation to new IDA API
  ppc: Convert mmu context allocation to new IDA API
  Convert net_namespace to new IDA API
  cb710: Convert to new IDA API
  rsxx: Convert to new IDA API
  osd: Convert to new IDA API
  sd: Convert to new IDA API
  ...

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
  ...

The call to strlcpy in backing_dev_store is incorrect. It should take
the size of the destination buffer instead of the size of the source
buffer.  Additionally, ignore the newline character (\n) when reading
the new file_name buffer. This makes it possible to set the backing_dev
as follows:

	echo /dev/sdX > /sys/block/zram0/backing_dev

The reason it worked before was the fact that strlcpy() copies 'len - 1'
bytes, which is strlen(buf) - 1 in our case, so it accidentally didn't
copy the trailing new line symbol.  Which also means that "echo -n
/dev/sdX" most likely was broken.

Signed-off-by: Peter Kalauskas <peskal@google.com>
Link: http://lkml.kernel.org/r/20180813061623.GC64836@rodete-desktop-imager.corp.google.com
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: <stable@vger.kernel.org>    [4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>