When a queue associated with a process remains empty, there are cases
where throughput gets boosted if the device is idled to await the
arrival of a new I/O request for that queue. Currently, BFQ assumes
that one of these cases is when the device has no internal queueing
(regardless of the properties of the I/O being served). Unfortunately,
this condition has proved to be too general. So, this commit refines it
as "the device has no internal queueing and is rotational".

This refinement provides a significant throughput boost with random
I/O, on flash-based storage without internal queueing. For example, on
a HiKey board, throughput increases by up to 125%, growing, e.g., from
6.9MB/s to 15.6MB/s with two or three random readers in parallel.
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Luca Miccio <lucmiccio@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The logic that decides whether to idle the device is scattered across
three functions. Almost all of the logic is in the function
bfq_bfqq_may_idle, but (1) part of the decision is made in
bfq_update_idle_window, and (2) the function bfq_bfqq_must_idle may
switch off idling regardless of the output of bfq_bfqq_may_idle. In
addition, both bfq_update_idle_window and bfq_bfqq_must_idle make
their decisions as a function of parameters that are used, for similar
purposes, also in bfq_bfqq_may_idle. This commit addresses these
issues by moving all the logic into bfq_bfqq_may_idle.
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We haven't used these in years, but somehow the definitions still
remained. Kill them, and renumber the QUEUE_FLAG_ space. We had
a hole in the beginning of the space, too.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Modify blk_mq_in_flight() to count both a partition and root at
the same time. Then we only have to call it once, instead of
potentially looping the tags twice.
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We don't have to inc/dec some counter, since we can just
iterate the tags. That makes inc/dec a noop, but means we
have to iterate busy tags to get an in-flight count.
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Instead of returning the count that matches the partition, pass
in an array of two ints. Index 0 will be filled with the inflight
count for the partition in question, and index 1 will filled
with the root inflight count, if the partition passed in is not the
root.

This is in preparation for being able to calculate both in one
go.
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

No functional change in this patch, just in preparation for
basing the inflight mechanism on the queue in question.
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Since we introduced blk-mq-sched, the tags->rqs[] array has been
dynamically assigned. So we need to check for NULL when iterating,
since there's a window of time where the bit is set, but we haven't
dynamically assigned the tags->rqs[] array position yet.

This is perfectly safe, since the memory backing of the request is
never going away while the device is alive.
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

This flag is never set right after calling bio_integrity_alloc,
so don't clear it and confuse the reader.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

This makes the code more obvious, and moves the most likely branch first
in the function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

set submit_queues to 1 by default, and make sure it's value > 0.
Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

make sure submit_queues equal nr_online_nodes.
Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

submit_bio_wait() does not consume bio reference. Add comment about
that.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We recently had a bug in the IPR SCSI driver, where it would end up
making the SCSI mid layer run the mq hardware queue with interrupts
disabled. This isn't legal, since the software queue locking relies
on never being grabbed from interrupt context. Additionally, drivers
that set BLK_MQ_F_BLOCKING may schedule from this context.

Add a WARN_ON_ONCE() to catch bad users up front.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We know we're in process context, so don't bother using the
IRQ safe versions of the spin lock.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

gcc-7 points out that a large controller number would overflow the
string length for the procfs name and the firmware version string:

drivers/block/DAC960.c: In function 'DAC960_Probe':
drivers/block/DAC960.c:6591:38: warning: 'sprintf' may write a terminating nul past the end of the destination [-Wformat-overflow=]
drivers/block/DAC960.c: In function 'DAC960_V1_ReadControllerConfiguration':
drivers/block/DAC960.c:1681:40: error: '%02d' directive writing between 2 and 3 bytes into a region of size between 2 and 5 [-Werror=format-overflow=]
drivers/block/DAC960.c:1681:40: note: directive argument in the range [0, 255]
drivers/block/DAC960.c:1681:3: note: 'sprintf' output between 10 and 14 bytes into a destination of size 12

Both of these seem appropriately sized, and using snprintf()
instead of sprintf() improves this by ensuring that even
incorrect data won't cause undefined behavior here.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently cfq/bfq/blk-throttle output cgroup info in trace in their own
way. Now we have standard blktrace API for this, so convert them to use
it.

Note, this changes the behavior a little bit. cgroup info isn't output
by default, we only do this with 'blk_cgroup' option enabled. cgroup
info isn't output as a string by default too, we only do this with
'blk_cgname' option enabled. Also cgroup info is output in different
position of the note string. I think these behavior changes aren't a big
issue (actually we make trace data shorter which is good), since the
blktrace note is solely for debugging.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

By default we output cgroup id in blktrace. This adds an option to
display cgroup path. Since get cgroup path is a relativly heavy
operation, we don't enable it by default.

with the option enabled, blktrace will output something like this:
dd-1353  [007] d..2   293.015252:   8,0   /test/level  D   R 24 + 8 [dd]
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blkcg_bio_issue_check() already gets blkcg for a BIO.
bio_associate_blkcg() uses a percpu refcounter, so it's a very cheap
operation. There is no point we don't attach the cgroup info into bio at
blkcg_bio_issue_check. This also makes blktrace outputs correct cgroup
info.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently blktrace isn't cgroup aware. blktrace prints out task name of
current context, but the task of current context isn't always in the
cgroup where the BIO comes from. We can't use task name to find out IO
cgroup. For example, Writeback BIOs always comes from flusher thread but
the BIOs are for different blk cgroups. Request could be requeued and
dispatched from completely different tasks. MD/DM are another examples.

This patch tries to fix the gap. We print out cgroup fhandle info in
blktrace. Userspace can use open_by_handle_at() syscall to find the
cgroup by fhandle. Or userspace can use name_to_handle_at() syscall to
find fhandle for a cgroup and use a BPF program to filter out blktrace
for a specific cgroup.

We add a new 'blk_cgroup' trace option for blk tracer. It's default off.
Application which doesn't know the new option isn't affected.  When it's
on, we output fhandle info right after blk_io_trace with an extra bit
set in event action. So from application point of view, blktrace with
the option will output new actions.

I didn't change blk trace event yet, since I'm not sure if changing the
trace event output is an ABI issue. If not, I'll do it later.
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add an API to export cgroup fhandle info. We don't export a full 'struct
file_handle', there are unrequired info. Sepcifically, cgroup is always
a directory, so we don't need a 'FILEID_INO32_GEN_PARENT' type fhandle,
we only need export the inode number and generation number just like
what generic_fh_to_dentry does. And we can avoid the overhead of getting
an inode too, since kernfs_node_id (ino and generation) has all the info
required.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now we have the facilities to implement exportfs operations. The idea is
cgroup can export the fhandle info to userspace, then userspace uses
fhandle to find the cgroup name. Another example is userspace can get
fhandle for a cgroup and BPF uses the fhandle to filter info for the
cgroup.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

inode number and generation can identify a kernfs node. We are going to
export the identification by exportfs operations, so put ino and
generation into a separate structure. It's convenient when later patches
use the identification.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When working on adding exportfs operations in kernfs, I found it's hard
to initialize dentry->d_fsdata in the exportfs operations. Looks there
is no way to do it without race condition. Look at the kernfs code
closely, there is no point to set dentry->d_fsdata. inode->i_private
already points to kernfs_node, and we can get inode from a dentry. So
this patch just delete the d_fsdata usage.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add an API to get kernfs node from inode number. We will need this to
implement exportfs operations.

This API will be used in blktrace too later, so it should be as fast as
possible. To make the API lock free, kernfs node is freed in RCU
context. And we depend on kernfs_node count/ino number to filter out
stale kernfs nodes.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Set i_generation for kernfs inode. This is required to implement
exportfs operations. The generation is 32-bit, so it's possible the
generation wraps up and we find stale files. To reduce the posssibility,
we don't reuse inode numer immediately. When the inode number allocation
wraps, we increase generation number. In this way generation/inode
number consist of a 64-bit number which is unlikely duplicated. This
does make the idr tree more sparse and waste some memory. Since idr
manages 32-bit keys, idr uses a 6-level radix tree, each level covers 6
bits of the key. In a 100k inode kernfs, the worst case will have around
300k radix tree node. Each node is 576bytes, so the tree will use about
~150M memory. Sounds not too bad, if this really is a problem, we should
find better data structure.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

kernfs uses ida to manage inode number. The problem is we can't get
kernfs_node from inode number with ida. Switching to use idr, next patch
will add an API to get kernfs_node from inode number.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull DeviceTree fixes from Rob Herring:
 "Two small DT fixes:

   - Fix error handling in of_irq_to_resource_table() due to
     of_irq_to_resource() error return changes.

   - Fix dtx_diff script due to dts include path changes"

* tag 'devicetree-fixes-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  of: irq: fix of_irq_to_resource() error check
  scripts/dtc: dtx_diff - update include dts paths to match build

Pull NFS client fixes from Anna Schumaker:
 "More NFS client bugfixes for 4.13.

  Most of these fix locking bugs that Ben and Neil noticed, but I also
  have a patch to fix one more access bug that was reported after last
  week.

  Stable fixes:
   - Fix a race where CB_NOTIFY_LOCK fails to wake a waiter
   - Invalidate file size when taking a lock to prevent corruption

  Other fixes:
   - Don't excessively generate tiny writes with fallocate
   - Use the raw NFS access mask in nfs4_opendata_access()"

* tag 'nfs-for-4.13-3' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter
  NFS: Optimize fallocate by refreshing mapping when needed.
  NFS: invalidate file size when taking a lock.
  NFS: Use raw NFS access mask in nfs4_opendata_access()

Pull xfs fixes from Darrick Wong:

 - fix firstfsb variables that we left uninitialized, which could lead
   to locking problems.

 - check for NULL metadata buffer pointers before using them.

 - don't allow btree cursor manipulation if the btree block is corrupt.
   Better to just shut down.

 - fix infinite loop problems in quotacheck.

 - fix buffer overrun when validating directory blocks.

 - fix deadlock problem in bunmapi.

* tag 'xfs-4.13-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix multi-AG deadlock in xfs_bunmapi
  xfs: check that dir block entries don't off the end of the buffer
  xfs: fix quotacheck dquot id overflow infinite loop
  xfs: check _alloc_read_agf buffer pointer before using
  xfs: set firstfsb to NULLFSBLOCK before feeding it to _bmapi_write
  xfs: check _btree_check_block value

Pull KVM fixes from Paolo Bonzini:
 "s390:
   - SRCU fix

  PPC:
   - host crash fixes

  x86:
   - bugfixes, including making nested posted interrupts really work

  Generic:
   - tweaks to kvm_stat and to uevents"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: LAPIC: Fix reentrancy issues with preempt notifiers
  tools/kvm_stat: add '-f help' to get the available event list
  tools/kvm_stat: use variables instead of hard paths in help output
  KVM: nVMX: Fix loss of L2's NMI blocking state
  KVM: nVMX: Fix posted intr delivery when vcpu is in guest mode
  x86: irq: Define a global vector for nested posted interrupts
  KVM: x86: do mask out upper bits of PAE CR3
  KVM: make pid available for uevents without debugfs
  KVM: s390: take srcu lock when getting/setting storage keys
  KVM: VMX: remove unused field
  KVM: PPC: Book3S HV: Fix host crash on changing HPT size
  KVM: PPC: Book3S HV: Enable TM before accessing TM registers

Pull xen fixes from Juergen Gross:
 "Three minor cleanups for xen related drivers"

* tag 'for-linus-4.13b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: dont fiddle with event channel masking in suspend/resume
  xen: selfballoon: remove unnecessary static in frontswap_selfshrink()
  xen: Drop un-informative message during boot

Pull arm64 fixes from Will Deacon:
 "I'd been collecting these whilst we debugged a CPU hotplug failure,
  but we ended up diagnosing that one to tglx, who has taken a fix via
  the -tip tree separately.

  We're seeing some NFS issues that we haven't gotten to the bottom of
  yet, and we've uncovered some issues with our backtracing too so there
  might be another fixes pull before we're done.

  Summary:

   - Ensure we have a guard page after the kernel image in vmalloc

   - Fix incorrect prefetch stride in copy_page

   - Ensure irqs are disabled in die()

   - Fix for event group validation in QCOM L2 PMU driver

   - Fix requesting of PMU IRQs on AMD Seattle

   - Minor cleanups and fixes"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mmu: Place guard page after mapping of kernel image
  drivers/perf: arm_pmu: Request PMU SPIs with IRQF_PER_CPU
  arm64: sysreg: Fix unprotected macro argmuent in write_sysreg
  perf: qcom_l2: fix column exclusion check
  arm64/lib: copy_page: use consistent prefetch stride
  arm64/numa: Drop duplicate message
  perf: Convert to using %pOF instead of full_name
  arm64: Convert to using %pOF instead of full_name
  arm64: traps: disable irq in die()
  arm64: atomics: Remove '&' from '+&' asm constraint in lse atomics
  arm64: uaccess: Remove redundant __force from addr cast in __range_ok

Pull powerpc fixes from Michael Ellerman:
 "The highlight is Ben's patch to work around a host killing bug when
  running KVM guests with the Radix MMU on Power9. See the long change
  log of that commit for more detail.

  And then three fairly minor fixes:

   - fix of_node_put() underflow during reconfig remove, using old DLPAR
     tools.

   - fix recently introduced ld version check with 64-bit LE-only
     toolchain.

   - free the subpage_prot_table correctly, avoiding a memory leak.

  Thanks to: Aneesh Kumar K.V, Benjamin Herrenschmidt, Laurent Vivier"

* tag 'powerpc-4.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm/hash: Free the subpage_prot_table correctly
  powerpc/Makefile: Fix ld version check with 64-bit LE-only toolchain
  powerpc/pseries: Fix of_node_put() underflow during reconfig remove
  powerpc/mm/radix: Workaround prefetch issue with KVM

nfs4_retry_setlk() sets the task's state to TASK_INTERRUPTIBLE within the
same region protected by the wait_queue's lock after checking for a
notification from CB_NOTIFY_LOCK callback.  However, after releasing that
lock, a wakeup for that task may race in before the call to
freezable_schedule_timeout_interruptible() and set TASK_WAKING, then
freezable_schedule_timeout_interruptible() will set the state back to
TASK_INTERRUPTIBLE before the task will sleep.  The result is that the task
will sleep for the entire duration of the timeout.

Since we've already set TASK_INTERRUPTIBLE in the locked section, just use
freezable_schedule_timout() instead.

Fixes: a1d617d8 ("nfs: allow blocking locks to be awoken by lock callbacks")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull crypto fixes from Herbert Xu:

 - remove broken dt bindings in inside-secure

 - fix authencesn crash when used with digest_null

 - fix cavium/nitrox firmware path

 - fix SHA3 failure in brcm

 - fix Kconfig dependency for brcm

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: authencesn - Fix digest_null crash
  crypto: brcm - remove BCM_PDC_MBOX dependency in Kconfig
  Documentation/bindings: crypto: remove the dma-mask property
  crypto: inside-secure - do not parse the dma mask from dt
  crypto: cavium/nitrox - Change in firmware path.
  crypto: brcm - Fix SHA3-512 algorithm failure

Pull btrfs fixes from David Sterba:
 "Fixes addressing problems reported by users, and there's one more
  regression fix"

* 'for-4.13-part3' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: round down size diff when shrinking/growing device
  Btrfs: fix early ENOSPC due to delalloc
  btrfs: fix lockup in find_free_extent with read-only block groups
  Btrfs: fix dir item validation when replaying xattr deletes

Pull MD fixes from Shaohua Li:
 "This fixes several bugs, three of them are marked for stable:

   - an initialization issue fixed by Ming

   - a bio clone race issue fixed by me

   - an async tx flush issue fixed by Ofer

   - other cleanups"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  MD: fix warnning for UP case
  md/raid5: add thread_group worker async_tx_issue_pending_all
  md: simplify code with bio_io_error
  md/raid1: fix writebehind bio clone
  md: raid1-10: move raid1/raid10 common code into raid1-10.c
  md: raid1/raid10: initialize bvec table via bio_add_page()
  md: remove 'idx' from 'struct resync_pages'

Merge tag 'for-4.13/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - a few DM integrity fixes that improve performance. One that address
   inefficiencies in the on-disk journal device layout. Another that
   makes use of the block layer's on-stack plugging when writing the
   journal.

 - a dm-bufio fix for the blk_status_t conversion that went in during
   the merge window.

 - a few DM raid fixes that address correctness when suspending the
   device and a validation fix for validation that occurs during device
   activation.

 - a couple DM zoned target fixes. Important one being the fix to not
   use GFP_KERNEL in the IO path due to concerns about deadlock in
   low-memory conditions (e.g. swap over a DM zoned device, etc).

 - a DM DAX device fix to make sure dm_dax_flush() is called if the
   underlying DAX device is operating as a write cache.

* tag 'for-4.13/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm, dax: Make sure dm_dax_flush() is called if device supports it
  dm verity fec: fix GFP flags used with mempool_alloc()
  dm zoned: use GFP_NOIO in I/O path
  dm zoned: remove test for impossible REQ_OP_FLUSH conditions
  dm raid: bump target version
  dm raid: avoid mddev->suspended access
  dm raid: fix activation check in validate_raid_redundancy()
  dm raid: remove WARN_ON() in raid10_md_layout_to_format()
  dm bufio: fix error code in dm_bufio_write_dirty_buffers()
  dm integrity: test for corrupted disk format during table load
  dm integrity: WARN_ON if variables representing journal usage get out of sync
  dm integrity: use plugging when writing the journal
  dm integrity: fix inefficient allocation of journal space

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

   - NVMe pull request from Christoph, with various fixes for nvme
     proper and nvme-fc.

   - disable runtime PM for blk-mq for now.

     With scsi now defaulting to using blk-mq, this reared its head as
     an issue. Longer term we'll fix up runtime PM for blk-mq, for now
     just disable it to prevent a hang on laptop resume for some folks.

   - blk-mq CPU <-> hw queue map fix from Christoph.

   - xen/blkfront pull request from Konrad, with two small fixes for the
     blkfront driver.

   - a few fixups for nbd from Joseph.

   - a stable fix for pblk from Javier"

* 'for-linus' of git://git.kernel.dk/linux-block:
  lightnvm: pblk: advance bio according to lba index
  nvme: validate admin queue before unquiesce
  nbd: clear disconnected on reconnect
  nvme-pci: fix HMB size calculation
  nvme-fc: revise TRADDR parsing
  nvme-fc: address target disconnect race conditions in fcp io submit
  nvme: fabrics commands should use the fctype field for data direction
  nvme: also provide a UUID in the WWID sysfs attribute
  xen/blkfront: always allocate grants first from per-queue persistent grants
  xen-blkfront: fix mq start/stop race
  blk-mq: map queues to all present CPUs
  block: disable runtime-pm for blk-mq
  xen-blkfront: Fix handling of non-supported operations
  nbd: only set sndtimeo if we have a timeout set
  nbd: take tx_lock before disconnecting
  nbd: allow multiple disconnects to be sent