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

If BLK_DEV_ZONED isn't set, 'ret' isn't used. This makes gcc complain,
rightfully. Move ret where it is used.

Fixes: 979d54475e0b ("null_blk: cleanup null_gendisk_register")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Queue dma alignment limit requires users(fs, target, ...) of block layer
to pass aligned buffer.

So far brd doesn't support un-aligned buffer, even though it is easy
to support it.

However, given brd is often used for debug purpose, and there are other
drivers which can't support un-aligned buffer too.

So add warning so that brd users know what to fix.

Reported-by: Stephen Rust <srust@blockbridge.com>
Cc: Stephen Rust <srust@blockbridge.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now we depend on blk_queue_split() to respect most of queue limit
(the only one exception could be dma alignment), however
blk_queue_split() isn't used for brd, so this limit isn't respected
since v4.3.

Also max_hw_sectors limit doesn't play a big role for brd, which is
added since brd is added to tree for unknown reason.

So remove it.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add a module_exit() to perform the necessary clean-up.

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

For each I/O request, blkback first maps the foreign pages for the
request to its local pages.  If an allocation of a local page for the
mapping fails, it should unmap every mapping already made for the
request.

However, blkback's handling mechanism for the allocation failure does
not mark the remaining foreign pages as unmapped.  Therefore, the unmap
function merely tries to unmap every valid grant page for the request,
including the pages not mapped due to the allocation failure.  On a
system that fails the allocation frequently, this problem leads to
following kernel crash.

  [  372.012538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
  [  372.012546] IP: [<ffffffff814071ac>] gnttab_unmap_refs.part.7+0x1c/0x40
  [  372.012557] PGD 16f3e9067 PUD 16426e067 PMD 0
  [  372.012562] Oops: 0002 [#1] SMP
  [  372.012566] Modules linked in: act_police sch_ingress cls_u32
  ...
  [  372.012746] Call Trace:
  [  372.012752]  [<ffffffff81407204>] gnttab_unmap_refs+0x34/0x40
  [  372.012759]  [<ffffffffa0335ae3>] xen_blkbk_unmap+0x83/0x150 [xen_blkback]
  ...
  [  372.012802]  [<ffffffffa0336c50>] dispatch_rw_block_io+0x970/0x980 [xen_blkback]
  ...
  Decompressing Linux... Parsing ELF... done.
  Booting the kernel.
  [    0.000000] Initializing cgroup subsys cpuset

This commit fixes this problem by marking the grant pages of the given
request that didn't mapped due to the allocation failure as invalid.

Fixes: c6cc142dac52 ("xen-blkback: use balloon pages for all mappings")

Reviewed-by: David Woodhouse <dwmw@amazon.de>
Reviewed-by: Maximilian Heyne <mheyne@amazon.de>
Reviewed-by: Paul Durrant <pdurrant@amazon.co.uk>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>