Pull block fixes from Jens Axboe:
 "A few fixes/changes that should go into this release:

   - null_blk zoned fixes (Damien)

   - blkdev_close() sync improvement (Douglas)

   - Fix regression in blk-iocost that impacted (at least) systemtap
     (Waiman)

   - Comment fix, header removal (Zhiqiang, Jianpeng)"

* tag 'block-5.7-2020-04-24' of git://git.kernel.dk/linux-block:
  null_blk: Cleanup zoned device initialization
  null_blk: Fix zoned command handling
  block: remove unused header
  blk-iocost: Fix error on iocost_ioc_vrate_adj
  bdev: Reduce time holding bd_mutex in sync in blkdev_close()
  buffer: remove useless comment and WB_REASON_FREE_MORE_MEM, reason.

Move all zoned mode related code from null_blk_main.c to
null_blk_zoned.c, avoiding an ugly #ifdef in the process.
Rename null_zone_init() into null_init_zoned_dev(), null_zone_exit()
into null_free_zoned_dev() and add the new function
null_register_zoned_dev() to finalize the zoned dev setup before
add_disk().

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

For write operations issued to a null_blk device with zoned mode
enabled, the state and write pointer position of the zone targeted by
the command should be checked before badblocks and memory backing
are handled as the write may be first failed due to, for instance, a
sector position not aligned with the zone write pointer. This order of
checking for errors reflects more accuratly the behavior of physical
zoned devices.

Furthermore, the write pointer position of the target zone should be
incremented only and only if no errors are reported by badblocks and
memory backing handling.

To fix this, introduce the small helper function null_process_cmd()
which execute null_handle_badblocks() and null_handle_memory_backed()
and use this function in null_zone_write() to correctly handle write
requests to zoned null devices depending on the type and state of the
write target zone. Also call this function in null_handle_zoned() to
process read requests to zoned null devices.

null_process_cmd() is called directly from null_handle_cmd() for
regular null devices, resulting in no functional change for these type
of devices. To have symmetric names, the function null_handle_zoned()
is renamed to null_process_zoned_cmd().

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull virtio fixes and cleanups from Michael Tsirkin:

 - Some bug fixes

 - Cleanup a couple of issues that surfaced meanwhile

 - Disable vhost on ARM with OABI for now - to be fixed fully later in
   the cycle or in the next release.

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (24 commits)
  vhost: disable for OABI
  virtio: drop vringh.h dependency
  virtio_blk: add a missing include
  virtio-balloon: Avoid using the word 'report' when referring to free page hinting
  virtio-balloon: make virtballoon_free_page_report() static
  vdpa: fix comment of vdpa_register_device()
  vdpa: make vhost, virtio depend on menu
  vdpa: allow a 32 bit vq alignment
  drm/virtio: fix up for include file changes
  remoteproc: pull in slab.h
  rpmsg: pull in slab.h
  virtio_input: pull in slab.h
  remoteproc: pull in slab.h
  virtio-rng: pull in slab.h
  virtgpu: pull in uaccess.h
  tools/virtio: make asm/barrier.h self contained
  tools/virtio: define aligned attribute
  virtio/test: fix up after IOTLB changes
  vhost: Create accessors for virtqueues private_data
  vdpasim: Return status in vdpasim_get_status
  ...

virtio_blk uses VIRTIO_RING_F_INDIRECT_DESC, pull in
the header defining that value.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

rbd_notify_op_lock() isn't interested in a notify reply.  Instead of
accepting that page vector just to free it, have watch-notify code take
care of it.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

rbd_dev->opts is used to distinguish between the image that is being
mapped and a parent.  However, because we no longer establish watch for
read-only mappings, this test is imprecise and results in unnecessary
rbd_unregister_watch() calls.

Make it consistent with need_watch in rbd_dev_image_probe().

Fixes: b9ef2b8858a0 ("rbd: don't establish watch for read-only mappings")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

rbd_dev_unprobe() is supposed to undo most of rbd_dev_image_probe(),
including rbd_dev_header_info(), which means that rbd_dev_header_info()
isn't supposed to be called after rbd_dev_unprobe().

However, rbd_dev_image_release() calls rbd_dev_unprobe() before
rbd_unregister_watch().  This is racy because a header update notify
can sneak in:

  "rbd unmap" thread                   ceph-watch-notify worker

  rbd_dev_image_release()
    rbd_dev_unprobe()
      free and zero out header
                                       rbd_watch_cb()
                                         rbd_dev_refresh()
                                           rbd_dev_header_info()
                                             read in header

The same goes for "rbd map" because rbd_dev_image_probe() calls
rbd_dev_unprobe() on errors.  In both cases this results in a memory
leak.

Fixes: fd22aef8b47c ("rbd: move rbd_unregister_watch() call into rbd_dev_image_release()")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

rbd_unregister_watch() flushes notifies and therefore cannot be called
under header_rwsem because a header update notify takes header_rwsem to
synchronize with "rbd map".  If mapping an image fails after the watch
is established and a header update notify sneaks in, we deadlock when
erroring out from rbd_dev_image_probe().

Move watch registration and unregistration out of the critical section.
The only reason they were put there was to make header_rwsem management
slightly more obvious.

Fixes: 811c66887746 ("rbd: fix rbd map vs notify races")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

Pull more xen updates from Juergen Gross:

 - two cleanups

 - fix a boot regression introduced in this merge window

 - fix wrong use of memory allocation flags

* tag 'for-linus-5.7-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: fix booting 32-bit pv guest
  x86/xen: make xen_pvmmu_arch_setup() static
  xen/blkfront: fix memory allocation flags in blkfront_setup_indirect()
  xen: Use evtchn_type_t as a type for event channels