As suggested by Davidlohr, we could refactor mutex_spin_on_owner().
Currently, we split up owner_running() with mutex_spin_on_owner().
When the owner changes, we make duplicate owner checks which are not
necessary. It also makes the code a bit obscure as we are using a
second check to figure out why we broke out of the loop.
This patch modifies it such that we remove the owner_running() function
and the mutex_spin_on_owner() loop directly checks for if the owner changes,
if the owner is not running, or if we need to reschedule. If the owner
changes, we break out of the loop and return true. If the owner is not
running or if we need to reschedule, then break out of the loop and return
false.
Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: chegu_vinod@hp.com
Cc: tglx@linutronix.de
Link: http://lkml.kernel.org/r/1422914367-5574-3-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the mutex_spin_on_owner(), we return true only if lock->owner == NULL.
This was beneficial in situations where there were multiple threads
simultaneously spinning for the mutex. If another thread got the lock
while other spinner(s) were also doing mutex_spin_on_owner(), then the
other spinners would stop spinning. This workaround helped reduce the
chance that many spinners were simultaneously spinning for the mutex
which can help reduce contention in highly contended cases.
However, recent changes were made to the optimistic spinning code such
that instead of having all spinners simultaneously spin for the mutex,
we queue the spinners with an MCS lock such that only one thread spins
for the mutex at a time. Furthermore, the OSQ optimizations ensure that
spinners in the queue will stop waiting if it needs to reschedule.
Now, we don't have to worry about multiple threads spinning on owner
at the same time, and if lock->owner is not NULL at this point, it likely
means another thread happens to obtain the lock in the fastpath. In this
case, it would make sense for the spinner to continue spinning as long
as the spinner doesn't need to schedule and the mutex owner is running.
This patch changes this so that mutex_spin_on_owner() returns true when
the lock owner changes, which means a thread will only stop spinning
if it either needs to reschedule or if the lock owner is not running.
We saw up to a 5% performance improvement in the fserver workload with
this patch.
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: chegu_vinod@hp.com
Cc: tglx@linutronix.de
Link: http://lkml.kernel.org/r/1422914367-5574-2-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Paravirt spinlock clears slowpath flag after doing unlock.
As explained by Linus currently it does:
prev = *lock;
add_smp(&lock->tickets.head, TICKET_LOCK_INC);
/* add_smp() is a full mb() */
if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))
__ticket_unlock_slowpath(lock, prev);
which is *exactly* the kind of things you cannot do with spinlocks,
because after you've done the "add_smp()" and released the spinlock
for the fast-path, you can't access the spinlock any more. Exactly
because a fast-path lock might come in, and release the whole data
structure.
Linus suggested that we should not do any writes to lock after unlock(),
and we can move slowpath clearing to fastpath lock.
So this patch implements the fix with:
1. Moving slowpath flag to head (Oleg):
Unlocked locks don't care about the slowpath flag; therefore we can keep
it set after the last unlock, and clear it again on the first (try)lock.
-- this removes the write after unlock. note that keeping slowpath flag would
result in unnecessary kicks.
By moving the slowpath flag from the tail to the head ticket we also avoid
the need to access both the head and tail tickets on unlock.
2. use xadd to avoid read/write after unlock that checks the need for
unlock_kick (Linus):
We further avoid the need for a read-after-release by using xadd;
the prev head value will include the slowpath flag and indicate if we
need to do PV kicking of suspended spinners -- on modern chips xadd
isn't (much) more expensive than an add + load.
Result:
setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest)
benchmark overcommit %improve
kernbench 1x -0.13
kernbench 2x 0.02
dbench 1x -1.77
dbench 2x -0.63
[Jeremy: Hinted missing TICKET_LOCK_INC for kick]
[Oleg: Moved slowpath flag to head, ticket_equals idea]
[PeterZ: Added detailed changelog]
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Fernando Luis Vázquez Cao <fernando_b1@lab.ntt.co.jp>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: a.ryabinin@samsung.com
Cc: dave@stgolabs.net
Cc: hpa@zytor.com
Cc: jasowang@redhat.com
Cc: jeremy@goop.org
Cc: paul.gortmaker@windriver.com
Cc: riel@redhat.com
Cc: tglx@linutronix.de
Cc: waiman.long@hp.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20150215173043.GA7471@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With task_blocks_on_rt_mutex() returning early -EDEADLK we never
add the waiter to the waitqueue. Later, we try to remove it via
remove_waiter() and go boom in rt_mutex_top_waiter() because
rb_entry() gives a NULL pointer.
( Tested on v3.18-RT where rtmutex is used for regular mutex and I
tried to get one twice in a row. )
Not sure when this started but I guess 397335f004 ("rtmutex: Fix
deadlock detector for real") or commit 3d5c9340d1 ("rtmutex:
Handle deadlock detection smarter").
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org> # for v3.16 and later kernels
Link: http://lkml.kernel.org/r/1424187823-19600-1-git-send-email-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 mm cleanups from Ingo Molnar:
"Two cleanups: simplify parse_setup_data() and sanitize_e820_map()
usage"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, e820: Clean up sanitize_e820_map() users
x86, setup: Let early_memremap() handle page alignment
Pull x86 SoC updates from Ingo Molnar:
"Various Intel Atom SoC updates (mostly to enhance debuggability), plus
an apb_timer cleanup"
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: pmc_atom: Expose contents of PSS
x86: pmc_atom: Clean up init function
x86: pmc-atom: Remove unused macro
x86: pmc_atom: don%27t check for NULL twice
x86: pmc-atom: Assign debugfs node as soon as possible
x86/platform: Remove unused function from apb_timer.c
Pull x86 fpu updates from Ingo Molnar:
"Initial round of kernel_fpu_begin/end cleanups from Oleg Nesterov,
plus a cleanup from Borislav Petkov"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, fpu: Fix math_state_restore() race with kernel_fpu_begin()
x86, fpu: Don't abuse has_fpu in __kernel_fpu_begin/end()
x86, fpu: Introduce per-cpu in_kernel_fpu state
x86/fpu: Use a symbolic name for asm operand
Pull EFI updates from Ingo Molnar:
"Main changes:
- Move efivarfs from the misc filesystem section to pseudo filesystem
- Expose firmware platform size in sysfs
- Improve robustness of get_memory_map() by removing assumptions on
the size of efi_memory_desc_t.
- various cleanups and fixes
The biggest risk is the get_memory_map() change, which changes the way
that both the arm64 and x86 EFI boot stub build the early memory map.
There are no known regressions with it at the moment, BYMMV"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi: Don't look for chosen@0 node on DT platforms
firmware: efi: Remove unneeded guid unparse
efi/libstub: Call get_memory_map() to obtain map and desc sizes
efi: Small leak on error in runtime map code
efi: rtc-efi: Mark UIE as unsupported
arm64/efi: efistub: Apply __init annotation
efi: Expose underlying UEFI firmware platform size to userland
efi: Rename efi_guid_unparse to efi_guid_to_str
efi: Update the URLs for efibootmgr
fs: Make efivarfs a pseudo filesystem, built by default with EFI
Pull x86 asm changes from Ingo Molnar:
"The main changes in this cycle were the x86/entry and sysret
enhancements from Andy Lutomirski, see merge commits 772a9aca12 and
b57c0b5175 for details"
[ Exectutive summary: IST exceptions that interrupt user space will run
on the regular kernel stack instead of the IST stack. Which
simplifies things particularly on return to user space.
The sysret cleanup ends up simplifying the logic on when we can use
sysret vs when we have to use iret. - Linus ]
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86_64, entry: Remove the syscall exit audit and schedule optimizations
x86_64, entry: Use sysret to return to userspace when possible
x86, traps: Fix ist_enter from userspace
x86, vdso: teach 'make clean' remove vdso64 binaries
x86_64 entry: Fix RCX for ptraced syscalls
x86: entry_64.S: fold SAVE_ARGS_IRQ macro into its sole user
x86: ia32entry.S: fix wrong symbolic constant usage: R11->ARGOFFSET
x86: entry_64.S: delete unused code
x86, mce: Get rid of TIF_MCE_NOTIFY and associated mce tricks
x86, traps: Add ist_begin_non_atomic and ist_end_non_atomic
x86: Clean up current_stack_pointer
x86, traps: Track entry into and exit from IST context
x86, entry: Switch stacks on a paranoid entry from userspace
Pull x86 APIC updates from Ingo Molnar:
"Continued fallout of the conversion of the x86 IRQ code to the
hierarchical irqdomain framework: more cleanups, simplifications,
memory allocation behavior enhancements, mainly in the interrupt
remapping and APIC code"
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
x86, init: Fix UP boot regression on x86_64
iommu/amd: Fix irq remapping detection logic
x86/acpi: Make acpi_[un]register_gsi_ioapic() depend on CONFIG_X86_LOCAL_APIC
x86: Consolidate boot cpu timer setup
x86/apic: Reuse apic_bsp_setup() for UP APIC setup
x86/smpboot: Sanitize uniprocessor init
x86/smpboot: Move apic init code to apic.c
init: Get rid of x86isms
x86/apic: Move apic_init_uniprocessor code
x86/smpboot: Cleanup ioapic handling
x86/apic: Sanitize ioapic handling
x86/ioapic: Add proper checks to setp/enable_IO_APIC()
x86/ioapic: Provide stub functions for IOAPIC%3Dn
x86/smpboot: Move smpboot inlines to code
x86/x2apic: Use state information for disable
x86/x2apic: Split enable and setup function
x86/x2apic: Disable x2apic from nox2apic setup
x86/x2apic: Add proper state tracking
x86/x2apic: Clarify remapping mode for x2apic enablement
x86/x2apic: Move code in conditional region
...
Pull timer updates from Ingo Molnar:
"The main changes in this cycle were:
- rework hrtimer expiry calculation in hrtimer_interrupt(): the
previous code had a subtle bug where expiry caching would miss an
expiry, resulting in occasional bogus (late) expiry of hrtimers.
- continuing Y2038 fixes
- ktime division optimization
- misc smaller fixes and cleanups"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hrtimer: Make __hrtimer_get_next_event() static
rtc: Convert rtc_set_ntp_time() to use timespec64
rtc: Remove redundant rtc_valid_tm() from rtc_hctosys()
rtc: Modify rtc_hctosys() to address y2038 issues
rtc: Update rtc-dev to use y2038-safe time interfaces
rtc: Update interface.c to use y2038-safe time interfaces
time: Expose get_monotonic_boottime64 for in-kernel use
time: Expose getboottime64 for in-kernel uses
ktime: Optimize ktime_divns for constant divisors
hrtimer: Prevent stale expiry time in hrtimer_interrupt()
ktime.h: Introduce ktime_ms_delta
Pull scheduler updates from Ingo Molnar:
"The main scheduler changes in this cycle were:
- various sched/deadline fixes and enhancements
- rescheduling latency fixes/cleanups
- rework the rq->clock code to be more consistent and more robust.
- minor micro-optimizations
- ->avg.decay_count fixes
- add a stack overflow check to might_sleep()
- idle-poll handler fix, possibly resulting in power savings
- misc smaller updates and fixes"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/Documentation: Remove unneeded word
sched/wait: Introduce wait_on_bit_timeout()
sched: Pull resched loop to __schedule() callers
sched/deadline: Remove cpu_active_mask from cpudl_find()
sched: Fix hrtick_start() on UP
sched/deadline: Avoid pointless __setscheduler()
sched/deadline: Fix stale yield state
sched/deadline: Fix hrtick for a non-leftmost task
sched/deadline: Modify cpudl::free_cpus to reflect rd->online
sched/idle: Add missing checks to the exit condition of cpu_idle_poll()
sched: Fix missing preemption opportunity
sched/rt: Reduce rq lock contention by eliminating locking of non-feasible target
sched/debug: Print rq->clock_task
sched/core: Rework rq->clock update skips
sched/core: Validate rq_clock*() serialization
sched/core: Remove check of p->sched_class
sched/fair: Fix sched_entity::avg::decay_count initialization
sched/debug: Fix potential call to __ffs(0) in sched_show_task()
sched/debug: Check for stack overflow in ___might_sleep()
sched/fair: Fix the dealing with decay_count in __synchronize_entity_decay()
Pull perf updates from Ingo Molnar:
"Kernel side changes:
- AMD range breakpoints support:
Extend breakpoint tools and core to support address range through
perf event with initial backend support for AMD extended
breakpoints.
The syntax is:
perf record -e mem:addr/len:type
For example set write breakpoint from 0x1000 to 0x1200 (0x1000 + 512)
perf record -e mem:0x1000/512:w
- event throttling/rotating fixes
- various event group handling fixes, cleanups and general paranoia
code to be more robust against bugs in the future.
- kernel stack overhead fixes
User-visible tooling side changes:
- Show precise number of samples in at the end of a 'record' session,
if processing build ids, since we will then traverse the whole
perf.data file and see all the PERF_RECORD_SAMPLE records,
otherwise stop showing the previous off-base heuristicly counted
number of "samples" (Namhyung Kim).
- Support to read compressed module from build-id cache (Namhyung
Kim)
- Enable sampling loads and stores simultaneously in 'perf mem'
(Stephane Eranian)
- 'perf diff' output improvements (Namhyung Kim)
- Fix error reporting for evsel pgfault constructor (Arnaldo Carvalho
de Melo)
Tooling side infrastructure changes:
- Cache eh/debug frame offset for dwarf unwind (Namhyung Kim)
- Support parsing parameterized events (Cody P Schafer)
- Add support for IP address formats in libtraceevent (David Ahern)
Plus other misc fixes"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
perf: Decouple unthrottling and rotating
perf: Drop module reference on event init failure
perf: Use POLLIN instead of POLL_IN for perf poll data in flag
perf: Fix put_event() ctx lock
perf: Fix move_group() order
perf: Fix event->ctx locking
perf: Add a bit of paranoia
perf symbols: Convert lseek + read to pread
perf tools: Use perf_data_file__fd() consistently
perf symbols: Support to read compressed module from build-id cache
perf evsel: Set attr.task bit for a tracking event
perf header: Set header version correctly
perf record: Show precise number of samples
perf tools: Do not use __perf_session__process_events() directly
perf callchain: Cache eh/debug frame offset for dwarf unwind
perf tools: Provide stub for missing pthread_attr_setaffinity_np
perf evsel: Don't rely on malloc working for sz 0
tools lib traceevent: Add support for IP address formats
perf ui/tui: Show fatal error message only if exists
perf tests: Fix typo in sample-parsing.c
...
Pull core locking updates from Ingo Molnar:
"The main changes are:
- mutex, completions and rtmutex micro-optimizations
- lock debugging fix
- various cleanups in the MCS and the futex code"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Optimize setting task running after being blocked
locking/rwsem: Use task->state helpers
sched/completion: Add lock-free checking of the blocking case
sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state
locking/mutex: Explicitly mark task as running after wakeup
futex: Fix argument handling in futex_lock_pi() calls
doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants
locking/Documentation: Update code path
softirq/preempt: Add missing current->preempt_disable_ip update
locking/osq: No need for load/acquire when acquire-polling
locking/mcs: Better differentiate between MCS variants
locking/mutex: Introduce ww_mutex_set_context_slowpath()
locking/mutex: Move MCS related comments to proper location
locking/mutex: Checking the stamp is WW only
Pull RCU updates from Ingo Molnar:
"The main RCU changes in this cycle are:
- Documentation updates.
- Miscellaneous fixes.
- Preemptible-RCU fixes, including fixing an old bug in the
interaction of RCU priority boosting and CPU hotplug.
- SRCU updates.
- RCU CPU stall-warning updates.
- RCU torture-test updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
rcu: Initialize tiny RCU stall-warning timeouts at boot
rcu: Fix RCU CPU stall detection in tiny implementation
rcu: Add GP-kthread-starvation checks to CPU stall warnings
rcu: Make cond_resched_rcu_qs() apply to normal RCU flavors
rcu: Optionally run grace-period kthreads at real-time priority
ksoftirqd: Use new cond_resched_rcu_qs() function
ksoftirqd: Enable IRQs and call cond_resched() before poking RCU
rcutorture: Add more diagnostics in rcu_barrier() test failure case
torture: Flag console.log file to prevent holdovers from earlier runs
torture: Add "-enable-kvm -soundhw pcspk" to qemu command line
rcutorture: Handle different mpstat versions
rcutorture: Check from beginning to end of grace period
rcu: Remove redundant rcu_batches_completed() declaration
rcutorture: Drop rcu_torture_completed() and friends
rcu: Provide rcu_batches_completed_sched() for TINY_RCU
rcutorture: Use unsigned for Reader Batch computations
rcutorture: Make build-output parsing correctly flag RCU's warnings
rcu: Make _batches_completed() functions return unsigned long
rcutorture: Issue warnings on close calls due to Reader Batch blows
documentation: Fix smp typo in memory-barriers.txt
...
Pull regulator updates from Mark Brown:
"This has not been a busy release for the regulator framework, though
we do have the first parts of some ongoing work from Bjorn Andersson
to allow us to support more complex modern systems with dynamic
configuration of regulators in suspend and idle states.
- Support for device-specific properties on regulator nodes when
using simplified DT parsing in the core from Krzysztof Kozlowski.
- Restructuring of the load tracking code, intended to support future
improvements in this area for more complex system designs.
- New drivers for Maxim MAX77843 and Mediatek MT6397.
- Lots of smaller fixes and improvements"
* tag 'regulator-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator: (29 commits)
regulator: max77843: Add max77843 regulator driver
regulator: Fix build breakage on !REGULATOR
regulator: Build sysfs entries with static attribute groups
regulator: qcom-rpm: Make it possible to specify supply
regulator: core: Consolidate drms update handling
regulator: qcom-rpm: signedness bug in probe()
regulator: da9211: Add gpio control for enable/disable of buck
regulator: qcom_rpm: Don't update vreg->uV/mV if rpm_reg_write fails
regulator: lp872x: Remove **regulators from struct lp872x
regulator: da9211: fix unmatched of_node
regulator: Update documentation after renaming function argument
regulator: axp20x: Migrate to regulator core's simplified DT parsing code
regulator: axp20x: Fill regulators_node and of_match descriptor fields
regulator: pfuze100-regulator: add pfuze3000 support
regulator: max77686: Document gpio properties
regulator: Allow parsing custom properties when using simplified DT parsing
regulator: max77686: Add GPIO control
regulator: Copy config passed during registration
regulator: tps65023: Constify struct regmap_config and regulator_ops
regulator: max8649: Constify struct regmap_config and regulator_ops
...
Pull spi updates from Mark Brown:
"The major highlight this release is a refactoring of the core to allow
us to run synchronous transfers in the context of the caller when
there is no contention for the bus. This improves performance in the
very common case by eliminating context switches and reducing the
number of hardware setup and teardown operations we need to perform.
Other changes:
- New drivers for DLN-2 USB-SPI adapter and ST SPI controllers.
- A big round of cleanups, performance and feature improvements for
the xilinx driver from Ricardo Ribalda Delgado.
- A wide range of smaller cleanups, fixes and feature improvements
throughout the subsystem"
* tag 'spi-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (68 commits)
spi: mxs: cleanup wait_for_completion return handling
spi: ti-qspi: cleanup wait_for_completion return handling
spi: spi-imx: cleanup wait_for_completion handling
spi: sh-msiof: cleanup wait_for_completion return handling
spi: match var type to return type of wait_for_completion
spi: spi-pxa2xx: only include mach/dma.h for legacy DMA
spi: atmel: cleanup wait_for_completion return handling
spi: fsl-dspi: Remove possible memory leak of 'chip'
spi: sh-msiof: Update calculation of frequency dividing
spi: spidev: Convert buf pointers for 32-bit compat SPI_IOC_MESSAGE(n)
spi/xilinx: Fix access invalid memory on xilinx_spi_tx
spi: Revert "spi/xilinx: Remove iowrite/ioread wrappers"
spi/xilinx: Check number of slaves range
spi/xilinx: Use polling mode on small transfers
spi/xilinx: Remove remaining_words driver data variable
spi/xilinx: Remove iowrite/ioread wrappers
spi/xilinx: Convert bits_per_word in bytes_per_word
spi/xilinx: Convert remainding_bytes in remaining words
spi/xilinx: Make spi_tx and spi_rx simmetric
spi/xilinx: Remove rx_fn and tx_fn pointer
...
Pull regmap updates from Mark Brown:
"A very quiet release for regmap this time around:
- Fix an endianness issue for I2C devices connected via SMBus where
we were getting two layers both trying to do endianness handling.
- Use a union to reduce the size of the regmap struct.
- A couple of smaller fixes"
* tag 'regmap-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
regmap: Fix i2c word access when using SMBus access functions
regmap: Export regmap_get_val_endian
regmap: ac97: Clean up indentation
regmap: correct the description of structure element in reg_field
regmap: Move spinlock_flags into the union
Pull hwmon updates from Guenter Roeck:
"Explicit support for ina231 added to ina2xx driver.
Minor improvements, cleanup and fixes in various drivers"
* tag 'hwmon-for-linus-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: (tmp102) add hibernation callbacks
hwmon: (ads2828) Only keep data in device data structure if needed
hwmon: (ads2828) Convert to use regmap
hwmon: (jc42) Allow negative hysteresis temperatures
hwmon: (adc128d818) Do proper sign extension
hwmon: (ad7314) Do proper sign extension
hwmon: (abx500) Fix format string warnings
hwmon: (jc42) Fix integer overflow when writing hysteresis value
hwmon: (jc42) Fix integer overflow
hwmon: (jc42) Use sign_extend32 for sign extension
hwmon: (ina2xx) Add ina231 compatible string
hwmon: (ina2xx) use DIV_ROUND_CLOSEST() to avoid rounding errors
hwmon: (ina2xx) remove an unnecessary dev_get_drvdata() result check
hwmon: (ina2xx) implement update_interval attribute for ina226
hwmon: (ina2xx) make shunt resistance configurable at run-time
hwmon: (ina2xx) don't accept shunt values greater than the calibration factor
hwmon: (ina2xx) remove a stray new line
hwmon: (ina2xx) reinitialize the chip in case it's been reset
hwmon: (nct7802) Constify struct regmap_config
There was a bad typo in commit 43759d4f42 ("random: use an improved
fast_mix() function") and I didn't notice because it "looked right", so
I saw what I expected to see when I reviewed it.
Only months later did I look and notice it's not the Threefish-inspired
mix function that I had designed and optimized.
Mea Culpa. Each input bit still has a chance to affect each output bit,
and the fast pool is spilled *long* before it fills, so it's not a total
disaster, but it's definitely not the intended great improvement.
I'm still working on finding better rotation constants. These are good
enough, but since it's unrolled twice, it's possible to get better
mixing for free by using eight different constants rather than repeating
the same four.
Signed-off-by: George Spelvin <linux@horizon.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Davidlohr Bueso
Oleg Nesterov
Jason Low
Raghavendra K T
Sebastian Andrzej Siewior
Linus Torvalds
George Spelvin