For normal filesystem IO, each page is added via blk_add_page(),
in which bvec(page) merge has been handled already, and basically
not possible to merge two adjacent bvecs in one bio.

So not try to merge two adjacent bvecs in blk_queue_split().

Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

XEN has special page merge requirement, see xen_biovec_phys_mergeable().
We can't merge pages into one bvec simply for XEN.

So move XEN's specific check on page merge into __bio_try_merge_page(),
then abvoid to break XEN by multi-page bvec.

Cc: ris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: xen-devel@lists.xenproject.org
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

xen_biovec_phys_mergeable() only needs .bv_page of the 2nd bio bvec
for checking if the two bvecs can be merged, so pass page to
xen_biovec_phys_mergeable() directly.

No function change.

Cc: ris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: xen-devel@lists.xenproject.org
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The loop driver always declares the rotational flag of its device as
rotational, even when the device of the mapped file is nonrotational,
as is the case with SSDs or on tmpfs. This can confuse filesystem tools
which are SSD-aware; in my case I frequently forget to tell mkfs.btrfs
that my loop device on tmpfs is nonrotational, and that I really don't
need any automatic metadata redundancy.

The attached patch fixes this by introspecting the rotational flag of the
mapped file's underlying block device, if it exists. If the mapped file's
filesystem has no associated block device - as is the case on e.g. tmpfs -
we assume nonrotational storage. If there is a better way to identify such
non-devices I'd love to hear them.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: holger@applied-asynchrony.com
Signed-off-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Benjamin Gordon <bmgordon@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The execution time of BFQ has been slightly lowered. Report the new
execution time in BFQ documentation.
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq saves the state of a queue each time a merge occurs, to be
able to resume such a state when the queue is associated again
with its original process, on a split.

Unfortunately bfq does not save & restore also the weight of the
queue. If the weight is not correctly resumed when the queue is
recycled, then the weight of the recycled queue could differ
from the weight of the original queue.

This commit adds the missing save & resume of the weight.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Francesco Pollicino <fra.fra.800@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The function "bfq_log_bfqq" prints the pid of the process
associated with the queue passed as input.

Unfortunately, if the queue is shared, then more than one process
is associated with the queue. The pid that gets printed in this
case is the pid of one of the associated processes.
Which process gets printed depends on the exact sequence of merge
events the queue underwent. So printing such a pid is rather
useless and above all is often rather confusing because it
reports a random pid between those of the associated processes.

This commit addresses this issue by printing SHARED instead of a pid
if the queue is shared.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Francesco Pollicino <fra.fra.800@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If many bfq_queues belonging to the same group happen to be created
shortly after each other, then the processes associated with these
queues have typically a common goal. In particular, bursts of queue
creations are usually caused by services or applications that spawn
many parallel threads/processes. Examples are systemd during boot, or
git grep. If there are no other active queues, then, to help these
processes get their job done as soon as possible, the best thing to do
is to reach a high throughput. To this goal, it is usually better to
not grant either weight-raising or device idling to the queues
associated with these processes. And this is exactly what BFQ
currently does.

There is however a drawback: if, in contrast, some other queues are
already active, then the newly created queues must be protected from
the I/O flowing through the already existing queues. In this case, the
best thing to do is the opposite as in the other case: it is much
better to grant weight-raising and device idling to the newly-created
queues, if they deserve it. This commit addresses this issue by doing
so if there are already other active queues.

This change also helps eliminating false positives, which occur when
the newly-created queues do not belong to an actual large burst of
creations, but some background task (e.g., a service) happens to
trigger the creation of new queues in the middle, i.e., very close to
when the victim queues are created. These false positive may cause
total loss of control on process latencies.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Sync random I/O is likely to be confused with soft real-time I/O,
because it is characterized by limited throughput and apparently
isochronous arrival pattern. To avoid false positives, this commits
prevents bfq_queues containing only random (seeky) I/O from being
tagged as soft real-time.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

To boost throughput with a set of processes doing interleaved I/O
(i.e., a set of processes whose individual I/O is random, but whose
merged cumulative I/O is sequential), BFQ merges the queues associated
with these processes, i.e., redirects the I/O of these processes into a
common, shared queue. In the shared queue, I/O requests are ordered by
their position on the medium, thus sequential I/O gets dispatched to
the device when the shared queue is served.

Queue merging costs execution time, because, to detect which queues to
merge, BFQ must maintain a list of the head I/O requests of active
queues, ordered by request positions. Measurements showed that this
costs about 10% of BFQ's total per-request processing time.

Request processing time becomes more and more critical as the speed of
the underlying storage device grows. Yet, fortunately, queue merging
is basically useless on the very devices that are so fast to make
request processing time critical. To reach a high throughput, these
devices must have many requests queued at the same time. But, in this
configuration, the internal scheduling algorithms of these devices do
also the job of queue merging: they reorder requests so as to obtain
as much as possible a sequential I/O pattern. As a consequence, with
processes doing interleaved I/O, the throughput reached by one such
device is likely to be the same, with and without queue merging.

In view of this fact, this commit disables queue merging, and all
related housekeeping, for non-rotational devices with internal
queueing. The total, single-lock-protected, per-request processing
time of BFQ drops to, e.g., 1.9 us on an Intel Core i7-2760QM@2.40GHz
(time measured with simple code instrumentation, and using the
throughput-sync.sh script of the S suite [1], in performance-profiling
mode). To put this result into context, the total,
single-lock-protected, per-request execution time of the lightest I/O
scheduler available in blk-mq, mq-deadline, is 0.7 us (mq-deadline is
~800 LOC, against ~10500 LOC for BFQ).

Disabling merging provides a further, remarkable benefit in terms of
throughput. Merging tends to make many workloads artificially more
uneven, mainly because of shared queues remaining non empty for
incomparably more time than normal queues. So, if, e.g., one of the
queues in a set of merged queues has a higher weight than a normal
queue, then the shared queue may inherit such a high weight and, by
staying almost always active, may force BFQ to perform I/O plugging
most of the time. This evidently makes it harder for BFQ to let the
device reach a high throughput.

As a practical example of this problem, and of the benefits of this
commit, we measured again the throughput in the nasty scenario
considered in previous commit messages: dbench test (in the Phoronix
suite), with 6 clients, on a filesystem with journaling, and with the
journaling daemon enjoying a higher weight than normal processes. With
this commit, the throughput grows from ~150 MB/s to ~200 MB/s on a
PLEXTOR PX-256M5 SSD. This is the same peak throughput reached by any
of the other I/O schedulers. As such, this is also likely to be the
maximum possible throughput reachable with this workload on this
device, because I/O is mostly random, and the other schedulers
basically just pass I/O requests to the drive as fast as possible.

[1] https://github.com/Algodev-github/STested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Francesco Pollicino <fra.fra.800@gmail.com>
Signed-off-by: Alessio Masola <alessio.masola@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The processes associated with a bfq_queue, say Q, may happen to
generate their cumulative I/O at a lower rate than the rate at which
the device could serve the same I/O. This is rather probable, e.g., if
only one process is associated with Q and the device is an SSD. It
results in Q becoming often empty while in service. If BFQ is not
allowed to switch to another queue when Q becomes empty, then, during
the service of Q, there will be frequent "service holes", i.e., time
intervals during which Q gets empty and the device can only consume
the I/O already queued in its hardware queues. This easily causes
considerable losses of throughput.

To counter this problem, BFQ implements a request injection mechanism,
which tries to fill the above service holes with I/O requests taken
from other bfq_queues. The hard part in this mechanism is finding the
right amount of I/O to inject, so as to both boost throughput and not
break Q's bandwidth and latency guarantees. To this goal, the current
version of this mechanism measures the bandwidth enjoyed by Q while it
is being served, and tries to inject the maximum possible amount of
extra service that does not cause Q's bandwidth to decrease too
much.

This solution has an important shortcoming. For bandwidth measurements
to be stable and reliable, Q must remain in service for a much longer
time than that needed to serve a single I/O request. Unfortunately,
this does not hold with many workloads. This commit addresses this
issue by changing the way the amount of injection allowed is
dynamically computed. It tunes injection as a function of the service
times of single I/O requests of Q, instead of Q's
bandwidth. Single-request service times are evidently meaningful even
if Q gets very few I/O requests completed while it is in service.

As a testbed for this new solution, we measured the throughput reached
by BFQ for one of the nastiest workloads and configurations for this
scheduler: the workload generated by the dbench test (in the Phoronix
suite), with 6 clients, on a filesystem with journaling, and with the
journaling daemon enjoying a higher weight than normal processes.
With this commit, the throughput grows from ~100 MB/s to ~150 MB/s on
a PLEXTOR PX-256M5.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Francesco Pollicino <fra.fra.800@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

In most cases, it is detrimental for throughput to plug I/O dispatch
when the in-service bfq_queue becomes temporarily empty (plugging is
performed to wait for the possible arrival, soon, of new I/O from the
in-service queue). There is however a case where plugging is needed
for service guarantees. If a bfq_queue, say Q, has a higher weight
than some other active bfq_queue, and is sync, i.e., contains sync
I/O, then, to guarantee that Q does receive a higher share of the
throughput than other lower-weight queues, it is necessary to plug I/O
dispatch when Q remains temporarily empty while being served.

For this reason, BFQ performs I/O plugging when some active bfq_queue
has a higher weight than some other active bfq_queue. But this is
unnecessarily overkill. In fact, if the in-service bfq_queue actually
has a weight lower than or equal to the other queues, then the queue
*must not* be guaranteed a higher share of the throughput than the
other queues. So, not plugging I/O cannot cause any harm to the
queue. And can boost throughput.

Taking advantage of this fact, this commit does not plug I/O for sync
bfq_queues with a weight lower than or equal to the weights of the
other queues. Here is an example of the resulting throughput boost
with the dbench workload, which is particularly nasty for BFQ. With
the dbench test in the Phoronix suite, BFQ reaches its lowest total
throughput with 6 clients on a filesystem with journaling, in case the
journaling daemon has a higher weight than normal processes. Before
this commit, the total throughput was ~80 MB/sec on a PLEXTOR PX-256M5,
after this commit it is ~100 MB/sec.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If a sync bfq_queue has a higher weight than some other queue, and
remains temporarily empty while in service, then, to preserve the
bandwidth share of the queue, it is necessary to plug I/O dispatching
until a new request arrives for the queue. In addition, a timeout
needs to be set, to avoid waiting for ever if the process associated
with the queue has actually finished its I/O.

Even with the above timeout, the device is however not fed with new
I/O for a while, if the process has finished its I/O. If this happens
often, then throughput drops and latencies grow. For this reason, the
timeout is kept rather low: 8 ms is the current default.

Unfortunately, such a low value may cause, on the opposite end, a
violation of bandwidth guarantees for a process that happens to issue
new I/O too late. The higher the system load, the higher the
probability that this happens to some process. This is a problem in
scenarios where service guarantees matter more than throughput. One
important case are weight-raised queues, which need to be granted a
very high fraction of the bandwidth.

To address this issue, this commit lower-bounds the plugging timeout
for weight-raised queues to 20 ms. This simple change provides
relevant benefits. For example, on a PLEXTOR PX-256M5S, with which
gnome-terminal starts in 0.6 seconds if there is no other I/O in
progress, the same applications starts in
- 0.8 seconds, instead of 1.2 seconds, if ten files are being read
  sequentially in parallel
- 1 second, instead of 2 seconds, if, in parallel, five files are
  being read sequentially, and five more files are being written
  sequentially
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Replace BFQ_GROUP_IOSCHED_ENABLED with CONFIG_BFQ_GROUP_IOSCHED.
Code under these ifdefs never worked, something might be broken.

Fixes: 0471559c ("block, bfq: add/remove entity weights correctly")
Fixes: 73d58118 ("block, bfq: consider also ioprio classes in symmetry detection")
Reviewed-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull KVM fixes from Paolo Bonzini:
 "A collection of x86 and ARM bugfixes, and some improvements to
  documentation.

  On top of this, a cleanup of kvm_para.h headers, which were exported
  by some architectures even though they not support KVM at all. This is
  responsible for all the Kbuild changes in the diffstat"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
  Documentation: kvm: clarify KVM_SET_USER_MEMORY_REGION
  KVM: doc: Document the life cycle of a VM and its resources
  KVM: selftests: complete IO before migrating guest state
  KVM: selftests: disable stack protector for all KVM tests
  KVM: selftests: explicitly disable PIE for tests
  KVM: selftests: assert on exit reason in CR4/cpuid sync test
  KVM: x86: update %rip after emulating IO
  x86/kvm/hyper-v: avoid spurious pending stimer on vCPU init
  kvm/x86: Move MSR_IA32_ARCH_CAPABILITIES to array emulated_msrs
  KVM: x86: Emulate MSR_IA32_ARCH_CAPABILITIES on AMD hosts
  kvm: don't redefine flags as something else
  kvm: mmu: Used range based flushing in slot_handle_level_range
  KVM: export <linux/kvm_para.h> and <asm/kvm_para.h> iif KVM is supported
  KVM: x86: remove check on nr_mmu_pages in kvm_arch_commit_memory_region()
  kvm: nVMX: Add a vmentry check for HOST_SYSENTER_ESP and HOST_SYSENTER_EIP fields
  KVM: SVM: Workaround errata#1096 (insn_len maybe zero on SMAP violation)
  KVM: Reject device ioctls from processes other than the VM's creator
  KVM: doc: Fix incorrect word ordering regarding supported use of APIs
  KVM: x86: fix handling of role.cr4_pae and rename it to 'gpte_size'
  KVM: nVMX: Do not inherit quadrant and invalid for the root shadow EPT
  ...

Pull x86 fixes from Thomas Gleixner:
 "A pile of x86 updates:

   - Prevent exceeding he valid physical address space in the /dev/mem
     limit checks.

   - Move all header content inside the header guard to prevent compile
     failures.

   - Fix the bogus __percpu annotation in this_cpu_has() which makes
     sparse very noisy.

   - Disable switch jump tables completely when retpolines are enabled.

   - Prevent leaking the trampoline address"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/realmode: Make set_real_mode_mem() static inline
  x86/cpufeature: Fix __percpu annotation in this_cpu_has()
  x86/mm: Don't exceed the valid physical address space
  x86/retpolines: Disable switch jump tables when retpolines are enabled
  x86/realmode: Don't leak the trampoline kernel address
  x86/boot: Fix incorrect ifdeffery scope
  x86/resctrl: Remove unused variable

Pull perf tooling fixes from Thomas Gleixner:
 "Core libraries:
   - Fix max perf_event_attr.precise_ip detection.
   - Fix parser error for uncore event alias
   - Fixup ordering of kernel maps after obtaining the main kernel map
     address.

  Intel PT:
   - Fix TSC slip where A TSC packet can slip past MTC packets so that
     the timestamp appears to go backwards.
   - Fixes for exported-sql-viewer GUI conversion to python3.

  ARM coresight:
   - Fix the build by adding a missing case value for enumeration value
     introduced in newer library, that now is the required one.

  tool headers:
   - Syncronize kernel headers with the kernel, getting new io_uring and
     pidfd_send_signal syscalls so that 'perf trace' can handle them"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf pmu: Fix parser error for uncore event alias
  perf scripts python: exported-sql-viewer.py: Fix python3 support
  perf scripts python: exported-sql-viewer.py: Fix never-ending loop
  perf machine: Update kernel map address and re-order properly
  tools headers uapi: Sync powerpc's asm/kvm.h copy with the kernel sources
  tools headers: Update x86's syscall_64.tbl and uapi/asm-generic/unistd
  tools headers uapi: Update drm/i915_drm.h
  tools arch x86: Sync asm/cpufeatures.h with the kernel sources
  tools headers uapi: Sync linux/fcntl.h to get the F_SEAL_FUTURE_WRITE addition
  tools headers uapi: Sync asm-generic/mman-common.h and linux/mman.h
  perf evsel: Fix max perf_event_attr.precise_ip detection
  perf intel-pt: Fix TSC slip
  perf cs-etm: Add missing case value

Pull CPU hotplug fixes from Thomas Gleixner:
 "Two SMT/hotplug related fixes:

   - Prevent crash when HOTPLUG_CPU is disabled and the CPU bringup
     aborts. This is triggered with the 'nosmt' command line option, but
     can happen by any abort condition. As the real unplug code is not
     compiled in, prevent the fail by keeping the CPU in zombie state.

   - Enforce HOTPLUG_CPU for SMP on x86 to avoid the above situation
     completely. With 'nosmt' being a popular option it's required to
     unplug the half brought up sibling CPUs (due to the MCE wreckage)
     completely"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y
  cpu/hotplug: Prevent crash when CPU bringup fails on CONFIG_HOTPLUG_CPU=n

Pull locking fixlet from Thomas Gleixner:
 "Trivial update to the maintainers file"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Remove deleted file from futex file pattern

Pull core fixes from Thomas Gleixner:
 "A small set of core updates:

   - Make the watchdog respect the selected CPU mask again. That was
     broken by the rework of the watchdog thread management and caused
     inconsistent state and NMI watchdog being unstoppable.

   - Ensure that the objtool build can find the libelf location.

   - Remove dead kcore stub code"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  watchdog: Respect watchdog cpumask on CPU hotplug
  objtool: Query pkg-config for libelf location
  proc/kcore: Remove unused kclist_add_remap()

Pull powerpc fixes from Michael Ellerman:
 "Three non-regression fixes.

   - Our optimised memcmp could read past the end of one of the buffers
     and potentially trigger a page fault leading to an oops.

   - Some of our code to read energy management data on PowerVM had an
     endian bug leading to bogus results.

   - When reporting a machine check exception we incorrectly reported
     TLB multihits as D-Cache multhits due to a missing entry in the
     array of causes.

  Thanks to: Chandan Rajendra, Gautham R. Shenoy, Mahesh Salgaonkar,
  Segher Boessenkool, Vaidyanathan Srinivasan"

* tag 'powerpc-5.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/pseries/mce: Fix misleading print for TLB mutlihit
  powerpc/pseries/energy: Use OF accessor functions to read ibm,drc-indexes
  powerpc/64: Fix memcmp reading past the end of src/dest

Pull dmaengine fixes from Vinod Koul:

 - Revert "dmaengine: stm32-mdma: Add a check on read_u32_array" as that
   caused regression

 - Fix MAINTAINER file uniphier-mdmac.c file path

* tag 'dmaengine-fix-5.1-rc3' of git://git.infradead.org/users/vkoul/slave-dma:
  MAINTAINERS: Fix uniphier-mdmac.c file path
  dmaengine: stm32-mdma: Revert "dmaengine: stm32-mdma: Add a check on read_u32_array"

Merge tag 'led-fixes-for-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED fixes from Jacek Anaszewski:

 - fix refcnt leak on interface rename

 - use memcpy in device_name_store() to avoid including garbage from a
   previous, longer value in the device_name

 - fix a potential NULL pointer dereference in case of_match_device()
   cannot find a match

* tag 'led-fixes-for-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: trigger: netdev: use memcpy in device_name_store
  leds: pca9532: fix a potential NULL pointer dereference
  leds: trigger: netdev: fix refcnt leak on interface rename

Pull GPIO fixes from Linus Walleij:
 "As you can see [in the git history] I was away on leave and Bartosz
  kindly stepped in and collected a slew of fixes, I pulled them into my
  tree in two sets and merged some two more fixes (fixing my own caused
  bugs) on top.

  Summary:

   - Revert the extended use of gpio_set_config() and think about how we
     can do this properly.

   - Fix up the SPI CS GPIO handling so it now works properly on the SPI
     bus children, as intended.

   - Error paths and driver fixes"

* tag 'gpio-v5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: mockup: use simple_read_from_buffer() in debugfs read callback
  gpio: of: Fix of_gpiochip_add() error path
  gpio: of: Check for "spi-cs-high" in child instead of parent node
  gpio: of: Check propname before applying "cs-gpios" quirks
  gpio: mockup: fix debugfs read
  Revert "gpio: use new gpio_set_config() helper in more places"
  gpio: aspeed: fix a potential NULL pointer dereference
  gpio: amd-fch: Fix bogus SPDX identifier
  gpio: adnp: Fix testing wrong value in adnp_gpio_direction_input
  gpio: exar: add a check for the return value of ida_simple_get fails

If userspace doesn't end the input with a newline (which can easily
happen if the write happens from a C program that does write(fd,
iface, strlen(iface))), we may end up including garbage from a
previous, longer value in the device_name. For example

# cat device_name

# printf 'eth12' > device_name
# cat device_name
eth12
# printf 'eth3' > device_name
# cat device_name
eth32

I highly doubt anybody is relying on this behaviour, so switch to
simply copying the bytes (we've already checked that size is <
IFNAMSIZ) and unconditionally zero-terminate it; of course, we also
still have to strip a trailing newline.

This is also preparation for future patches.

Fixes: 06f502f5 ("leds: trigger: Introduce a NETDEV trigger")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

In case of_match_device cannot find a match, return -EINVAL to avoid
NULL pointer dereference.

Fixes: fa4191a6 ("leds: pca9532: Add device tree support")
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

Pull staging driver fixes from Greg KH:
 "Here are some small staging driver fixes for 5.1-rc3, and one driver
  removal.

  The biggest thing here is the removal of the mt7621-eth driver as a
  "real" network driver was merged in 5.1-rc1 for this hardware, so this
  old driver can now be removed.

  Other than that, there are just a number of small fixes, all resolving
  reported issues and some potential corner cases for error handling
  paths.

  All of these have been in linux-next with no reported issues"

* tag 'staging-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: vt6655: Remove vif check from vnt_interrupt
  staging: erofs: keep corrupted fs from crashing kernel in erofs_readdir()
  staging: octeon-ethernet: fix incorrect PHY mode
  staging: vc04_services: Fix an error code in vchiq_probe()
  staging: erofs: fix error handling when failed to read compresssed data
  staging: vt6655: Fix interrupt race condition on device start up.
  staging: rtlwifi: Fix potential NULL pointer dereference of kzalloc
  staging: rtl8712: uninitialized memory in read_bbreg_hdl()
  staging: rtlwifi: rtl8822b: fix to avoid potential NULL pointer dereference
  staging: rtl8188eu: Fix potential NULL pointer dereference of kcalloc
  staging, mt7621-pci: fix build without pci support
  staging: speakup_soft: Fix alternate speech with other synths
  staging: axis-fifo: add CONFIG_OF dependency
  staging: olpc_dcon_xo_1: add missing 'const' qualifier
  staging: comedi: ni_mio_common: Fix divide-by-zero for DIO cmdtest
  staging: erofs: fix to handle error path of erofs_vmap()
  staging: mt7621-dts: update ethernet settings.
  staging: remove mt7621-eth

Pull tty/serial fixes from Greg KH:
 "Here are some small tty and serial driver fixes for 5.1-rc3.

  Nothing major here, just a number of potential problems fixes for
  error handling paths, as well as some other minor bugfixes for
  reported issues with 5.1-rc1.

  All of these have been in linux-next with no reported issues"

* tag 'tty-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: fix NULL pointer issue when tty_port ops is not set
  Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdboc
  dt-bindings: serial: Add compatible for Mediatek MT8183
  tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped
  tty/serial: atmel: Add is_half_duplex helper
  serial: sh-sci: Fix setting SCSCR_TIE while transferring data
  serial: ar933x_uart: Fix build failure with disabled console
  tty: serial: qcom_geni_serial: Initialize baud in qcom_geni_console_setup
  sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()
  tty: mxs-auart: fix a potential NULL pointer dereference
  tty: atmel_serial: fix a potential NULL pointer dereference
  serial: max310x: Fix to avoid potential NULL pointer dereference
  serial: mvebu-uart: Fix to avoid a potential NULL pointer dereference

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for 5.1-rc3.

  Nothing major at all here, just a small collection of fixes for
  reported issues, and potential problems with error handling paths.
  Also a few new device ids, as normal.

  All of these have been in linux-next with no reported issues"

* tag 'usb-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (25 commits)
  USB: serial: option: add Olicard 600
  USB: serial: cp210x: add new device id
  usb: u132-hcd: fix resource leak
  usb: cdc-acm: fix race during wakeup blocking TX traffic
  usb: mtu3: fix EXTCON dependency
  usb: usb251xb: fix to avoid potential NULL pointer dereference
  usb: core: Try generic PHY_MODE_USB_HOST if usb_phy_roothub_set_mode fails
  phy: sun4i-usb: Support set_mode to USB_HOST for non-OTG PHYs
  xhci: Don't let USB3 ports stuck in polling state prevent suspend
  usb: xhci: dbc: Don't free all memory with spinlock held
  xhci: Fix port resume done detection for SS ports with LPM enabled
  USB: serial: mos7720: fix mos_parport refcount imbalance on error path
  USB: gadget: f_hid: fix deadlock in f_hidg_write()
  usb: gadget: net2272: Fix net2272_dequeue()
  usb: gadget: net2280: Fix net2280_dequeue()
  usb: gadget: net2280: Fix overrun of OUT messages
  usb: dwc3: pci: add support for Comet Lake PCH ID
  usb: usb251xb: Remove unnecessary comparison of unsigned integer with >= 0
  usb: common: Consider only available nodes for dr_mode
  usb: typec: tcpm: Try PD-2.0 if sink does not respond to 3.0 source-caps
  ...

Pull ACPI fix from Rafael Wysocki:
 "This corrects a previous attempt to make Linux use its own set of ACPI
  debug flags different from the upstream ACPICA's default (Erik
  Schmauss)"

* tag 'acpi-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: use different default debug value than ACPICA

Pull power management fixes from Rafael Wysocki:
 "These fix CPU base frequency reporting in the intel_pstate driver and
  a use-after-free in the scpi-cpufreq driver.

  Specifics:

   - Fix the ACPI CPPC library to actually follow the specification when
     decoding the guaranteed performance register information and make
     the intel_pstate driver to fall back to the nominal frequency when
     reporting the base frequency if the guaranteed performance register
     information is not there (Srinivas Pandruvada).

   - Fix use-after-free in the exit callback of the scpi-cpufreq left
     after an update during the 5.0 development cycle (Vincent Stehlé)"

* tag 'pm-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: scpi: Fix use after free
  cpufreq: intel_pstate: Also use CPPC nominal_perf for base_frequency
  ACPI / CPPC: Fix guaranteed performance handling

Pull security layer fixes from James Morris:
 "Yama and LSM config fixes"

* 'fixes-v5.1-a' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  LSM: Revive CONFIG_DEFAULT_SECURITY_* for "make oldconfig"
  Yama: mark local symbols as static

Merge misc fixes from Andrew Morton:
 "22 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (22 commits)
  fs/proc/proc_sysctl.c: fix NULL pointer dereference in put_links
  fs: fs_parser: fix printk format warning
  checkpatch: add %pt as a valid vsprintf extension
  mm/migrate.c: add missing flush_dcache_page for non-mapped page migrate
  drivers/block/zram/zram_drv.c: fix idle/writeback string compare
  mm/page_isolation.c: fix a wrong flag in set_migratetype_isolate()
  mm/memory_hotplug.c: fix notification in offline error path
  ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK
  fs/proc/kcore.c: make kcore_modules static
  include/linux/list.h: fix list_is_first() kernel-doc
  mm/debug.c: fix __dump_page when mapping->host is not set
  mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified
  include/linux/hugetlb.h: convert to use vm_fault_t
  iommu/io-pgtable-arm-v7s: request DMA32 memory, and improve debugging
  mm: add support for kmem caches in DMA32 zone
  ocfs2: fix inode bh swapping mixup in ocfs2_reflink_inodes_lock
  mm/hotplug: fix offline undo_isolate_page_range()
  fs/open.c: allow opening only regular files during execve()
  mailmap: add Changbin Du
  mm/debug.c: add a cast to u64 for atomic64_read()
  ...

Pull arm64 fix from Catalin Marinas:
 "Use memblock_alloc() instead of memblock_alloc_low() in
  request_standard_resources(), the latter being limited to the low 4G
  memory range on arm64"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: replace memblock_alloc_low with memblock_alloc

Pull IOMMU fixes from Joerg Roedel:

 - Fix a bug in the AMD IOMMU driver not handling exclusion ranges
   correctly. In fact the driver did not reserve these ranges for IOVA
   allocations, so that dma-handles could be allocated in an exclusion
   range, leading to data corruption. Exclusion ranges have not been
   used by any firmware up to now, so this issue remained undiscovered
   for quite some time.

 - Fix wrong warning messages that the IOMMU core code prints when it
   tries to allocate the default domain for an iommu group and the
   driver does not support any of the default domain types (like Intel
   VT-d).

* tag 'iommu-fixes-v5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Reserve exclusion range in iova-domain
  iommu: Don't print warning when IOMMU driver only supports unmanaged domains

Pull driver core fix from Greg KH:
 "Here is a single driver core patch for 5.1-rc3.

  After 5.1-rc1, all of the users of BUS_ATTR() are finally removed, so
  we can now drop this macro from include/linux/device.h so that no more
  new users will be created.

  This patch has been in linux-next for a while, with no reported
  issues"

* tag 'driver-core-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver core: remove BUS_ATTR()

Pull char/misc driver fixes from Greg KH:
 "Here are some binder, habanalabs, and vboxguest driver fixes for
  5.1-rc3.

  The Binder fixes resolve some reported issues found by testing, first
  by the selinux developers, and then earlier today by syzbot.

  The habanalabs fixes are all minor, resolving a number of tiny things.

  The vboxguest patches are a bit larger. They resolve the fact that
  virtual box decided to change their api in their latest release in a
  way that broke the existing kernel code, despite saying that they were
  never going to do that. So this is a bit of a "new feature", but is
  good to get merged so that 5.1 will work with the latest release. The
  changes are not large and of course virtual box "swears" they will not
  break this again, but no one is holding their breath here.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  virt: vbox: Implement passing requestor info to the host for VirtualBox 6.0.x
  binder: fix race between munmap() and direct reclaim
  binder: fix BUG_ON found by selinux-testsuite
  habanalabs: cast to expected type
  habanalabs: prevent host crash during suspend/resume
  habanalabs: perform accounting for active CS
  habanalabs: fix mapping with page size bigger than 4KB
  habanalabs: complete user context cleanup before hard reset
  habanalabs: fix bug when mapping very large memory area
  habanalabs: fix MMU number of pages calculation

Pull SCSI fixes from James Bottomley:
 "Thirteen fixes, seven of which are for IBM fibre channel and three
  additional for fairly serious bugs in drivers (qla2xxx, mpt3sas,
  aacraid).

  Of the three core fixes, the most significant is probably the missed
  run queue causing an indefinite hang. The others are fixing a
  potential use after free on device close and silencing an incorrect
  warning"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: ibmvfc: Clean up transport events
  scsi: ibmvfc: Byte swap status and error codes when logging
  scsi: ibmvfc: Add failed PRLI to cmd_status lookup array
  scsi: ibmvfc: Remove "failed" from logged errors
  scsi: zfcp: reduce flood of fcrscn1 trace records on multi-element RSCN
  scsi: zfcp: fix scsi_eh host reset with port_forced ERP for non-NPIV FCP devices
  scsi: zfcp: fix rport unblock if deleted SCSI devices on Scsi_Host
  scsi: sd: Quiesce warning if device does not report optimal I/O size
  scsi: sd: Fix a race between closing an sd device and sd I/O
  scsi: core: Run queue when state is set to running after being blocked
  scsi: qla4xxx: fix a potential NULL pointer dereference
  scsi: aacraid: Insure we don't access PCIe space during AER/EEH
  scsi: mpt3sas: Fix kernel panic during expander reset

Pull i2c fixes from Wolfram Sang:
 "A new ID for the i801 driver and some Documentation fixes to make it
  easier for people to find the bindings (which is also a basis for
  further improvements in that area)"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: wmt: make bindings file name match the driver
  i2c: sun6i-p2wi: make bindings file name match the driver
  i2c: stu300: make bindings file name match the driver
  i2c: mt65xx: make bindings file name match the driver
  i2c: iop3xx: make bindings file name match the driver
  i2c: i801: Add support for Intel Comet Lake