Pull block fixes from Jens Axboe:
 "Let's try this one again, this time without the compat_ioctl changes.
  We've got those fixed up, but that can go out next week.

  This contains:

   - block queue flush lockdep annotation (Bart)

   - Type fix for bsg_queue_rq() (Bart)

   - Three dasd fixes (Stefan, Jan)

   - nbd deadlock fix (Mike)

   - Error handling bio user map fix (Yang)

   - iocost fix (Tejun)

   - sbitmap waitqueue addition fix that affects the kyber IO scheduler
     (David)"

* tag 'block-5.5-20191221' of git://git.kernel.dk/linux-block:
  sbitmap: only queue kyber's wait callback if not already active
  block: fix memleak when __blk_rq_map_user_iov() is failed
  s390/dasd: fix typo in copyright statement
  s390/dasd: fix memleak in path handling error case
  s390/dasd/cio: Interpret ccw_device_get_mdc return value correctly
  block: Fix a lockdep complaint triggered by request queue flushing
  block: Fix the type of 'sts' in bsg_queue_rq()
  block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT
  nbd: fix shutdown and recv work deadlock v2
  iocost: over-budget forced IOs should schedule async delay

Pull xen fixes from Juergen Gross:
 "This contains two cleanup patches and a small series for supporting
  reloading the Xen block backend driver"

* tag 'for-linus-5.5b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/grant-table: remove multiple BUG_ON on gnttab_interface
  xen-blkback: support dynamic unbind/bind
  xen/interface: re-define FRONT/BACK_RING_ATTACH()
  xenbus: limit when state is forced to closed
  xenbus: move xenbus_dev_shutdown() into frontend code...
  xen/blkfront: Adjust indentation in xlvbd_alloc_gendisk

By simply re-attaching to shared rings during connect_ring() rather than
assuming they are freshly allocated (i.e assuming the counters are zero)
it is possible for vbd instances to be unbound and re-bound from and to
(respectively) a running guest.

This has been tested by running:

while true;
  do fio --name=randwrite --ioengine=libaio --iodepth=16 \
  --rw=randwrite --bs=4k --direct=1 --size=1G --verify=crc32;
  done

in a PV guest whilst running:

while true;
  do echo vbd-$DOMID-$VBD >unbind;
  echo unbound;
  sleep 5;
  echo vbd-$DOMID-$VBD >bind;
  echo bound;
  sleep 3;
  done

in dom0 from /sys/bus/xen-backend/drivers/vbd to continuously unbind and
re-bind its system disk image.

This is a highly useful feature for a backend module as it allows it to be
unloaded and re-loaded (i.e. updated) without requiring domUs to be halted.
This was also tested by running:

while true;
  do echo vbd-$DOMID-$VBD >unbind;
  echo unbound;
  sleep 5;
  rmmod xen-blkback;
  echo unloaded;
  sleep 1;
  modprobe xen-blkback;
  echo bound;
  cd $(pwd);
  sleep 3;
  done

in dom0 whilst running the same loop as above in the (single) PV guest.

Some (less stressful) testing has also been done using a Windows HVM guest
with the latest 9.0 PV drivers installed.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

Clang warns:

../drivers/block/xen-blkfront.c:1117:4: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
                nr_parts = PARTS_PER_DISK;
                ^
../drivers/block/xen-blkfront.c:1115:3: note: previous statement is here
                if (err)
                ^

This is because there is a space at the beginning of this line; remove
it so that the indentation is consistent according to the Linux kernel
coding style and clang no longer warns.

While we are here, the previous line has some trailing whitespace; clean
that up as well.

Fixes: c80a420995e7 ("xen-blkfront: handle Xen major numbers other than XENVBD")
Link: https://github.com/ClangBuiltLinux/linux/issues/791
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

This fixes a regression added with:

commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie <mchristi@redhat.com>
Date:   Sun Aug 4 14:10:06 2019 -0500

    nbd: fix max number of supported devs

where we can deadlock during device shutdown. The problem occurs if
the recv_work's nbd_config_put occurs after nbd_start_device_ioctl has
returned and the userspace app has droppped its reference via closing
the device and running nbd_release. The recv_work nbd_config_put call
would then drop the refcount to zero and try to destroy the config which
would try to do destroy_workqueue from the recv work.

This patch just has nbd_start_device_ioctl do a flush_workqueue when it
wakes so we know after the ioctl returns running works have exited. This
also fixes a possible race where we could try to reuse the device while
old recv_works are still running.

Cc: stable@vger.kernel.org
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull xen fixes from Juergen Gross:
 "Two fixes: one for a resource accounting bug in some configurations
  and a fix for another patch which went into rc1"

* tag 'for-linus-5.5b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: fix ballooned page accounting without hotplug enabled
  xen-blkback: prevent premature module unload

Objects allocated by xen_blkif_alloc come from the 'blkif_cache' kmem
cache. This cache is destoyed when xen-blkif is unloaded so it is
necessary to wait for the deferred free routine used for such objects to
complete. This necessity was missed in commit 14855954f636 "xen-blkback:
allow module to be cleanly unloaded". This patch fixes the problem by
taking/releasing extra module references in xen_blkif_alloc/free()
respectively.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

Pull more xen updates from Juergen Gross:

 - a patch to fix a build warning

 - a cleanup of no longer needed code in the Xen event handling

 - a small series for the Xen grant driver avoiding high order
   allocations and replacing an insane global limit by a per-call one

 - a small series fixing Xen frontend/backend module referencing

* tag 'for-linus-5.5b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen-blkback: allow module to be cleanly unloaded
  xen/xenbus: reference count registered modules
  xen/gntdev: switch from kcalloc() to kvcalloc()
  xen/gntdev: replace global limit of mapped pages by limit per call
  xen/gntdev: remove redundant non-zero check on ret
  xen/events: remove event handling recursion detection

Pull more block and io_uring updates from Jens Axboe:
 "I wasn't expecting this to be so big, and if I was, I would have used
  separate branches for this. Going forward I'll be doing separate
  branches for the current tree, just like for the next kernel version
  tree. In any case, this contains:

   - Series from Christoph that fixes an inherent race condition with
     zoned devices and revalidation.

   - null_blk zone size fix (Damien)

   - Fix for a regression in this merge window that caused busy spins by
     sending empty disk uevents (Eric)

   - Fix for a regression in this merge window for bfq stats (Hou)

   - Fix for io_uring creds allocation failure handling (me)

   - io_uring -ERESTARTSYS send/recvmsg fix (me)

   - Series that fixes the need for applications to retain state across
     async request punts for io_uring. This one is a bit larger than I
     would have hoped, but I think it's important we get this fixed for
     5.5.

   - connect(2) improvement for io_uring, handling EINPROGRESS instead
     of having applications needing to poll for it (me)

   - Have io_uring use a hash for poll requests instead of an rbtree.
     This turned out to work much better in practice, so I think we
     should make the switch now. For some workloads, even with a fair
     amount of cancellations, the insertion sort is just too expensive.
     (me)

   - Various little io_uring fixes (me, Jackie, Pavel, LimingWu)

   - Fix for brd unaligned IO, and a warning for the future (Ming)

   - Fix for a bio integrity data leak (Justin)

   - bvec_iter_advance() improvement (Pavel)

   - Xen blkback page unmap fix (SeongJae)

  The major items in here are all well tested, and on the liburing side
  we continue to add regression and feature test cases. We're up to 50
  topic cases now, each with anywhere from 1 to more than 10 cases in
  each"

* tag 'for-linus-20191205' of git://git.kernel.dk/linux-block: (33 commits)
  block: fix memleak of bio integrity data
  io_uring: fix a typo in a comment
  bfq-iosched: Ensure bio->bi_blkg is valid before using it
  io_uring: hook all linked requests via link_list
  io_uring: fix error handling in io_queue_link_head
  io_uring: use hash table for poll command lookups
  io-wq: clear node->next on list deletion
  io_uring: ensure deferred timeouts copy necessary data
  io_uring: allow IO_SQE_* flags on IORING_OP_TIMEOUT
  null_blk: remove unused variable warning on !CONFIG_BLK_DEV_ZONED
  brd: warn on un-aligned buffer
  brd: remove max_hw_sectors queue limit
  xen/blkback: Avoid unmapping unmapped grant pages
  io_uring: handle connect -EINPROGRESS like -EAGAIN
  block: set the zone size in blk_revalidate_disk_zones atomically
  block: don't handle bio based drivers in blk_revalidate_disk_zones
  block: allocate the zone bitmaps lazily
  block: replace seq_zones_bitmap with conv_zones_bitmap
  block: simplify blkdev_nr_zones
  block: remove the empty line at the end of blk-zoned.c
  ...

Pull ceph updates from Ilya Dryomov:
 "The two highlights are a set of improvements to how rbd read-only
  mappings are handled and a conversion to the new mount API (slightly
  complicated by the fact that we had a common option parsing framework
  that called out into rbd and the filesystem instead of them calling
  into it).

  Also included a few scattered fixes and a MAINTAINERS update for rbd,
  adding Dongsheng as a reviewer"

* tag 'ceph-for-5.5-rc1' of git://github.com/ceph/ceph-client:
  libceph, rbd, ceph: convert to use the new mount API
  rbd: ask for a weaker incompat mask for read-only mappings
  rbd: don't query snapshot features
  rbd: remove snapshot existence validation code
  rbd: don't establish watch for read-only mappings
  rbd: don't acquire exclusive lock for read-only mappings
  rbd: disallow read-write partitions on images mapped read-only
  rbd: treat images mapped read-only seriously
  rbd: introduce RBD_DEV_FLAG_READONLY
  rbd: introduce rbd_is_snap()
  ceph: don't leave ino field in ceph_mds_request_head uninitialized
  ceph: tone down loglevel on ceph_mdsc_build_path warning
  rbd: update MAINTAINERS info
  ceph: fix geting random mds from mdsmap
  rbd: fix spelling mistake "requeueing" -> "requeuing"
  ceph: make several helper accessors take const pointers
  libceph: drop unnecessary check from dispatch() in mon_client.c