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Now that the rcu_node structures' ->completed fields are unconditionally
assigned at grace-period cleanup time, they should already have the
correct value for the new grace period at grace-period initialization
time. This commit therefore inserts a WARN_ON_ONCE() to verify this
invariant.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Preemption greatly raised the probability of certain types of race
conditions, so this commit adds an anti-heisenbug to greatly increase
the collision cross section, also known as the probability of occurrence.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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The current approach to grace-period initialization is vulnerable to
extremely low-probability races. These races stem from the fact that
the old grace period is marked completed on the same traversal through
the rcu_node structure that is marking the start of the new grace period.
This means that some rcu_node structures will believe that the old grace
period is still in effect at the same time that other rcu_node structures
believe that the new grace period has already started.
These sorts of disagreements can result in too-short grace periods,
as shown in the following scenario:
1. CPU 0 completes a grace period, but needs an additional
grace period, so starts initializing one, initializing all
the non-leaf rcu_node structures and the first leaf rcu_node
structure. Because CPU 0 is both completing the old grace
period and starting a new one, it marks the completion of
the old grace period and the start of the new grace period
in a single traversal of the rcu_node structures.
Therefore, CPUs corresponding to the first rcu_node structure
can become aware that the prior grace period has completed, but
CPUs corresponding to the other rcu_node structures will see
this same prior grace period as still being in progress.
2. CPU 1 passes through a quiescent state, and therefore informs
the RCU core. Because its leaf rcu_node structure has already
been initialized, this CPU's quiescent state is applied to the
new (and only partially initialized) grace period.
3. CPU 1 enters an RCU read-side critical section and acquires
a reference to data item A. Note that this CPU believes that
its critical section started after the beginning of the new
grace period, and therefore will not block this new grace period.
4. CPU 16 exits dyntick-idle mode. Because it was in dyntick-idle
mode, other CPUs informed the RCU core of its extended quiescent
state for the past several grace periods. This means that CPU 16
is not yet aware that these past grace periods have ended. Assume
that CPU 16 corresponds to the second leaf rcu_node structure --
which has not yet been made aware of the new grace period.
5. CPU 16 removes data item A from its enclosing data structure
and passes it to call_rcu(), which queues a callback in the
RCU_NEXT_TAIL segment of the callback queue.
6. CPU 16 enters the RCU core, possibly because it has taken a
scheduling-clock interrupt, or alternatively because it has
more than 10,000 callbacks queued. It notes that the second
most recent grace period has completed (recall that because it
corresponds to the second as-yet-uninitialized rcu_node structure,
it cannot yet become aware that the most recent grace period has
completed), and therefore advances its callbacks. The callback
for data item A is therefore in the RCU_NEXT_READY_TAIL segment
of the callback queue.
7. CPU 0 completes initialization of the remaining leaf rcu_node
structures for the new grace period, including the structure
corresponding to CPU 16.
8. CPU 16 again enters the RCU core, again, possibly because it has
taken a scheduling-clock interrupt, or alternatively because
it now has more than 10,000 callbacks queued. It notes that
the most recent grace period has ended, and therefore advances
its callbacks. The callback for data item A is therefore in
the RCU_DONE_TAIL segment of the callback queue.
9. All CPUs other than CPU 1 pass through quiescent states. Because
CPU 1 already passed through its quiescent state, the new grace
period completes. Note that CPU 1 is still in its RCU read-side
critical section, still referencing data item A.
10. Suppose that CPU 2 wais the last CPU to pass through a quiescent
state for the new grace period, and suppose further that CPU 2
did not have any callbacks queued, therefore not needing an
additional grace period. CPU 2 therefore traverses all of the
rcu_node structures, marking the new grace period as completed,
but does not initialize a new grace period.
11. CPU 16 yet again enters the RCU core, yet again possibly because
it has taken a scheduling-clock interrupt, or alternatively
because it now has more than 10,000 callbacks queued. It notes
that the new grace period has ended, and therefore advances
its callbacks. The callback for data item A is therefore in
the RCU_DONE_TAIL segment of the callback queue. This means
that this callback is now considered ready to be invoked.
12. CPU 16 invokes the callback, freeing data item A while CPU 1
is still referencing it.
This scenario represents a day-zero bug for TREE_RCU. This commit
therefore ensures that the old grace period is marked completed in
all leaf rcu_node structures before a new grace period is marked
started in any of them.
That said, it would have been insanely difficult to force this race to
happen before the grace-period initialization process was preemptible.
Therefore, this commit is not a candidate for -stable.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Conflicts:
kernel/rcutree.c
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The module parameters blimit, qhimark, and qlomark (and more
recently, rcu_fanout_leaf) have permission masks of zero, so
that their values are not visible from sysfs. This is unnecessary
and inconvenient to administrators who might like an easy way to
see what these values are on a running system. This commit therefore
sets their permission masks to 0444, allowing them to be read but
not written.
Reported-by: Rusty Russell <rusty@ozlabs.org>
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Although almost everyone is well-served by the defaults, some uses of RCU
benefit from shorter grace periods, while others benefit more from the
greater efficiency provided by longer grace periods. Situations requiring
a large number of grace periods to elapse (and wireshark startup has
been called out as an example of this) are helped by lower-latency
grace periods. Furthermore, in some embedded applications, people are
willing to accept a small degradation in update efficiency (due to there
being more of the shorter grace-period operations) in order to gain the
lower latency.
In contrast, those few systems with thousands of CPUs need longer grace
periods because the CPU overhead of a grace period rises roughly
linearly with the number of CPUs. Such systems normally do not make
much use of facilities that require large numbers of grace periods to
elapse, so this is a good tradeoff.
Therefore, this commit allows the durations to be controlled from sysfs.
There are two sysfs parameters, one named "jiffies_till_first_fqs" that
specifies the delay in jiffies from the end of grace-period initialization
until the first attempt to force quiescent states, and the other named
"jiffies_till_next_fqs" that specifies the delay (again in jiffies)
between subsequent attempts to force quiescent states. They both default
to three jiffies, which is compatible with the old hard-coded behavior.
At some future time, it may be possible to automatically increase the
grace-period length with the number of CPUs, but we do not yet have
sufficient data to do a good job. Preliminary data indicates that we
should add an addiitonal jiffy to each of the delays for every 200 CPUs
in the system, but more experimentation is needed. For now, the number
of systems with more than 1,000 CPUs is small enough that this can be
relegated to boot-time hand tuning.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Large systems running RCU_FAST_NO_HZ kernels see extreme memory
contention on the rcu_state structure's ->fqslock field. This
can be avoided by disabling RCU_FAST_NO_HZ, either at compile time
or at boot time (via the nohz kernel boot parameter), but large
systems will no doubt become sensitive to energy consumption.
This commit therefore uses a combining-tree approach to spread the
memory contention across new cache lines in the leaf rcu_node structures.
This can be thought of as a tournament lock that has only a try-lock
acquisition primitive.
The effect on small systems is minimal, because such systems have
an rcu_node "tree" consisting of a single node. In addition, this
functionality is not used on fastpaths.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Moving quiescent-state forcing into a kthread dispenses with the need
for the ->n_rp_need_fqs field, so this commit removes it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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RCU quiescent-state forcing is currently carried out without preemption
points, which can result in excessive latency spikes on large systems
(many hundreds or thousands of CPUs). This patch therefore inserts
a voluntary preemption point into force_qs_rnp(), which should greatly
reduce the magnitude of these spikes.
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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As the first step towards allowing quiescent-state forcing to be
preemptible, this commit moves RCU quiescent-state forcing into the
same kthread that is now used to initialize and clean up after grace
periods. This is yet another step towards keeping scheduling
latency down to a dull roar.
Updated to change from raw_spin_lock_irqsave() to raw_spin_lock_irq()
and to remove the now-unused rcu_state structure fields as suggested by
Peter Zijlstra.
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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The fields in the rcu_state structure that are protected by the
root rcu_node structure's ->lock can share a cache line with the
fields protected by ->onofflock. This can result in excessive
memory contention on large systems, so this commit applies
____cacheline_internodealigned_in_smp to the ->onofflock field in
order to segregate them.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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In kernels built with CONFIG_RCU_FAST_NO_HZ=y, CPUs can accumulate a
large number of lazy callbacks, which as the name implies will be slow
to be invoked. This can be a problem on small-memory systems, where the
default 6-second sleep for CPUs having only lazy RCU callbacks could well
be fatal. This commit therefore installs an OOM hander that ensures that
every CPU with lazy callbacks has at least one non-lazy callback, in turn
ensuring timely advancement for these callbacks.
Updated to fix bug that disabled OOM killing, noted by Lai Jiangshan.
Updated to push the for_each_rcu_flavor() loop into rcu_oom_notify_cpu(),
thus reducing the number of IPIs, as suggested by Steven Rostedt. Also
to make the for_each_online_cpu() loop be preemptible. (Later, it might
be good to use smp_call_function(), as suggested by Peter Zijlstra.)
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Earlier versions of RCU invoked the RCU core from the CPU_DYING notifier
in order to note a quiescent state for the outgoing CPU. Because the
CPU is marked "offline" during the execution of the CPU_DYING notifiers,
the RCU core had to tolerate being invoked from an offline CPU. However,
commit b1420f1c (Make rcu_barrier() less disruptive) left only tracing
code in the CPU_DYING notifier, so the RCU core need no longer execute
on offline CPUs. This commit therefore enforces this restriction.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Then rcu_gp_kthread() function is too large and furthermore needs to
have the force_quiescent_state() code pulled in. This commit therefore
breaks up rcu_gp_kthread() into rcu_gp_init() and rcu_gp_cleanup().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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RCU grace-period cleanup is currently carried out with interrupts
disabled, which can result in excessive latency spikes on large systems
(many hundreds or thousands of CPUs). This patch therefore makes the
RCU grace-period cleanup be preemptible, including voluntary preemption
points, which should eliminate those latency spikes. Similar spikes from
forcing of quiescent states will be dealt with similarly by later patches.
Updated to replace uses of spin_lock_irqsave() with spin_lock_irq(), as
suggested by Peter Zijlstra.
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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As a first step towards allowing grace-period cleanup to be preemptible,
this commit moves the RCU grace-period cleanup into the same kthread
that is now used to initialize grace periods. This is needed to keep
scheduling latency down to a dull roar.
[ paulmck: Get rid of stray spin_lock_irqsave() calls. ]
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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RCU grace-period initialization is currently carried out with interrupts
disabled, which can result in 200-microsecond latency spikes on systems
on which RCU has been configured for 4096 CPUs. This patch therefore
makes the RCU grace-period initialization be preemptible, which should
eliminate those latency spikes. Similar spikes from grace-period cleanup
and the forcing of quiescent states will be dealt with similarly by later
patches.
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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The next step in reducing RCU's grace-period initialization latency on
large systems will make this initialization preemptible. Unfortunately,
making the grace-period initialization subject to interrupts (let alone
preemption) exposes the following race on systems whose rcu_node tree
contains more than one node:
1. CPU 31 starts initializing the grace period, including the
first leaf rcu_node structures, and is then preempted.
2. CPU 0 refers to the first leaf rcu_node structure, and notes
that a new grace period has started. It passes through a
quiescent state shortly thereafter, and informs the RCU core
of this rite of passage.
3. CPU 0 enters an RCU read-side critical section, acquiring
a pointer to an RCU-protected data item.
4. CPU 31 takes an interrupt whose handler removes the data item
referenced by CPU 0 from the data structure, and registers an
RCU callback in order to free it.
5. CPU 31 resumes initializing the grace period, including its
own rcu_node structure. In invokes rcu_start_gp_per_cpu(),
which advances all callbacks, including the one registered
in #4 above, to be handled by the current grace period.
6. The remaining CPUs pass through quiescent states and inform
the RCU core, but CPU 0 remains in its RCU read-side critical
section, still referencing the now-removed data item.
7. The grace period completes and all the callbacks are invoked,
including the one that frees the data item that CPU 0 is still
referencing. Oops!!!
One way to avoid this race is to remove grace-period acceleration from
rcu_start_gp_per_cpu(). Now, the only reason for this acceleration was
to allow CPUs bringing RCU out of idle state to have their callbacks
invoked after only one grace period, rather than the two grace periods
that would otherwise be required. But this acceleration does not
work when RCU grace-period initialization is moved to a kthread because
the CPU posting the callback is no longer necessarily the CPU that is
initializing the resulting grace period.
This commit therefore removes this now-pointless (and soon to be dangerous)
grace-period acceleration, thus avoiding the above race.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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As the first step towards allowing grace-period initialization to be
preemptible, this commit moves the RCU grace-period initialization
into its own kthread. This is needed to keep large-system scheduling
latency at reasonable levels.
Also change raw_spin_lock_irqsave() to raw_spin_lock_irq() as suggested
by Peter Zijlstra in review comments.
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Each grace period is supposed to have at least one callback waiting
for that grace period to complete. However, if CONFIG_NO_HZ=n, an
extra callback-free grace period is no big problem -- it will chew up
a tiny bit of CPU time, but it will complete normally. In contrast,
CONFIG_NO_HZ=y kernels have the potential for all the CPUs to go to
sleep indefinitely, in turn indefinitely delaying completion of the
callback-free grace period. Given that nothing is waiting on this grace
period, this is also not a problem.
That is, unless RCU CPU stall warnings are also enabled, as they are
in recent kernels. In this case, if a CPU wakes up after at least one
minute of inactivity, an RCU CPU stall warning will result. The reason
that no one noticed until quite recently is that most systems have enough
OS noise that they will never remain absolutely idle for a full minute.
But there are some embedded systems with cut-down userspace configurations
that consistently get into this situation.
All this begs the question of exactly how a callback-free grace period
gets started in the first place. This can happen due to the fact that
CPUs do not necessarily agree on which grace period is in progress.
If a CPU still believes that the grace period that just completed is
still ongoing, it will believe that it has callbacks that need to wait for
another grace period, never mind the fact that the grace period that they
were waiting for just completed. This CPU can therefore erroneously
decide to start a new grace period. Note that this can happen in
TREE_RCU and TREE_PREEMPT_RCU even on a single-CPU system: Deadlock
considerations mean that the CPU that detected the end of the grace
period is not necessarily officially informed of this fact for some time.
Once this CPU notices that the earlier grace period completed, it will
invoke its callbacks. It then won't have any callbacks left. If no
other CPU has any callbacks, we now have a callback-free grace period.
This commit therefore makes CPUs check more carefully before starting a
new grace period. This new check relies on an array of tail pointers
into each CPU's list of callbacks. If the CPU is up to date on which
grace periods have completed, it checks to see if any callbacks follow
the RCU_DONE_TAIL segment, otherwise it checks to see if any callbacks
follow the RCU_WAIT_TAIL segment. The reason that this works is that
the RCU_WAIT_TAIL segment will be promoted to the RCU_DONE_TAIL segment
as soon as the CPU is officially notified that the old grace period
has ended.
This change is to cpu_needs_another_gp(), which is called in a number
of places. The only one that really matters is in rcu_start_gp(), where
the root rcu_node structure's ->lock is held, which prevents any
other CPU from starting or completing a grace period, so that the
comparison that determines whether the CPU is missing the completion
of a grace period is stable.
Reported-by: Becky Bruce <bgillbruce@gmail.com>
Reported-by: Subodh Nijsure <snijsure@grid-net.com>
Reported-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Walmsley <paul@pwsan.com> # OMAP3730, OMAP4430
Cc: stable@vger.kernel.org
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git://git.linaro.org/people/ljones/linux-3.0-ux500 into next/dt
* 'for-arm-soc-next' of git://git.linaro.org/people/ljones/linux-3.0-ux500:
ARM: ux500: Fix SSP register address format
ARM: ux500: Apply tc3589x's GPIO/IRQ properties to HREF's DT
ARM: ux500: Remove redundant #gpio-cell properties from Snowball DT
ARM: ux500: Add all encompassing sound node to the HREF Device Tree
ARM: ux500: Add nodes for the MSP into the HREF Device Tree
ARM: ux500: Add all known I2C sub-device nodes to the HREF DT
ARM: ux500: Stop registering I2C sub-devices for HREF when DT is enabled
ARM: ux500: Stop registering Audio devices for HREF when DT is enabled
ARM: ux500: Add all encompassing sound node to the Snowball Device Tree
ARM: ux500: Add nodes for the MSP into Device Tree
ARM: ux500: Rename MSP board file to something more meaningful
ARM: ux500: Remove platform registration of MSP devices
ARM: ux500: Stop registering the MOP500 Audio driver from platform code
ARM: ux500: Pass MSP DMA platform data though AUXDATA
ARM: ux500: Fork MSP platform registration for step-by-step DT enablement
ARM: ux500: Add AB8500 CODEC node to DB8500 Device Tree
ARM: ux500: Clean-up MSP platform code
ARM: ux500: Pass SDI DMA information though AUX_DATA to MMCI
ARM: ux500: Add UART support to the HREF Device Tree
ARM: ux500: Add skeleton Device Tree for the HREF reference board
...
+ sync to v3.6-rc6
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we need to grab mutex before the reference counter reaches 0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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normally we deal with lock_mount()/umount races by checking that
mountpoint to be is still in our namespace after lock_mount() has
been done. However, do_add_mount() skips that check when called
with MNT_SHRINKABLE in flags (i.e. from finish_automount()). The
reason is that ->mnt_ns may be a temporary namespace created exactly
to contain automounts a-la NFS4 referral handling. It's not the
namespace of the caller, though, so check_mnt() would fail here.
We still need to check that ->mnt_ns is non-NULL in that case,
though.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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When PPPOE is running over a virtual ethernet interface (e.g., a
bonding interface) and the user tries to delete the interface in case
the PPPOE state is ZOMBIE, the kernel will loop forever while
unregistering net_device for the reference count is not decreased to
zero which should have been done with dev_put().
Signed-off-by: Xiaodong Xu <stid.smth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pull MIPS fixes from Ralf Baechle:
"Random fixes across arch/mips, essentially.
One fix for an issue in get_user_pages_fast() which previously was
discovered on x86, a miscalculation in the support for the MIPS MT
hardware multithreading support, the RTC support for the Malta and a
fix for a spurious interrupt issue that seems to bite only very
special Malta configurations."
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MIPS: Malta: Don't crash on spurious interrupt.
MIPS: Malta: Remove RTC Data Mode bootstrap breakage
MIPS: mm: Add compound tail page _mapcount when mapped
MIPS: CMP/SMTC: Fix tc_id calculation
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On some hw, link is not up during adding iface to team. That causes event
not being sent to userspace and that may cause confusion.
Fix this bug by sending port changed event once it's added to team.
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pull ARM and clkdev fixes from Russell King:
"Two patches for clkdev which resolve the long standing issue that the
devm_* versions were dependent on clkdev, which they shouldn't have
been. Instead, they're dependent on HAVE_CLK instead, which implies
that you're providing clk_get() and clk_put().
A small fix to the ARM decompressor to ensure that the page tables are
properly interpreted by the CPU, and reserve syscall 378 for kcmp (the
checksyscalls.sh script is unfortunately currently broken so arch
maintainers aren't getting notified of new syscalls...)
Lastly, a larger fix for an issue between the common clk subsystem and
smp_twd which causes warnings to be spat out."
* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
ARM: reserve syscall 378 for kcmp
ARM: 7535/1: Reprogram smp_twd based on new common clk framework notifiers
ARM: 7537/1: clk: Fix release in devm_clk_put()
ARM: 7532/1: decompressor: reset SCTLR.TRE for VMSA ARMv7 cores
ARM: 7534/1: clk: Make the managed clk functions generically available
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
Pull HID fixes from Jiri Kosina:
"The most important fix is Logitech Unifying receiver regression in
device enumeration fix from Nestor Lopez Casado. In addition to that,
there is a small memory leak fix for Thinkpad keyboard driver from
Axel Lin."
* 'upstream-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
HID: Fix logitech-dj: missing Unifying device issue
HID: lenovo-tpkbd: Fix memory leak in tpkbd_remove_tp()
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Pull cifs fix from Steve French.
* 'for-linus' of git://git.samba.org/sfrench/cifs-2.6:
cifs: fix return value in cifsConvertToUTF16
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icmp_filter() should not modify its input, or else its caller
would need to recompute ip_hdr() if skb->head is reallocated.
Use skb_header_pointer() instead of pskb_may_pull() and
change the prototype to make clear both sk and skb are const.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Currently the driver has no MODULE_LICENSE attribute in its source which
results in a kernel taint if I load this:
root@(none):~# modprobe bcm87xx
bcm87xx: module license 'unspecified' taints kernel.
Since the first lines of the source code clearly state:
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file "COPYING" in the main directory of this
* archive for more details.
I think it's safe to add the MODULE_LICENSE("GPL") macro and thus remove
the kernel taint.
Cc: stable@vger.kernel.org
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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__iomem annotation cleanup branch from Arnd.
* cleanup/__iomem: (21 commits)
net: seeq: use __iomem pointers for MMIO
video: da8xx-fb: use __iomem pointers for MMIO
scsi: eesox: use __iomem pointers for MMIO
serial: ks8695: use __iomem pointers for MMIO
input: rpcmouse: use __iomem pointers for MMIO
ARM: samsung: use __iomem pointers for MMIO
ARM: spear13xx: use __iomem pointers for MMIO
ARM: sa1100: use __iomem pointers for MMIO
ARM: prima2: use __iomem pointers for MMIO
ARM: nomadik: use __iomem pointers for MMIO
ARM: msm: use __iomem pointers for MMIO
ARM: lpc32xx: use __iomem pointers for MMIO
ARM: ks8695: use __iomem pointers for MMIO
ARM: ixp4xx: use __iomem pointers for MMIO
ARM: iop32x: use __iomem pointers for MMIO
ARM: iop13xx: use __iomem pointers for MMIO
ARM: integrator: use __iomem pointers for MMIO
ARM: imx: use __iomem pointers for MMIO
ARM: ebsa110: use __iomem pointers for MMIO
ARM: at91: use __iomem pointers for MMIO
...
Signed-off-by: Olof Johansson <olof@lixom.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless into for-davem
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into regmap-next
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If the config contains CONFIG_IIO_BUFFER=y and CONFIG_IIO_SIMPLE_DUMMY_BUFFER=n
iio_simple_dummy_configure_buffer() is stubbed out and iio_buffer_register() is
not. As a result we try to register a buffer which has not been configured.
This will causes a NULL pointer deref in iio_buffer_register. To solve this
issue move the iio_buffer_register() call to iio_simple_dummy_configure_buffer(),
so it will only be called if iio_simple_dummy_configure_buffer() has been called.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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Driver to allow use of the ADC drivers supported by the IIO
subsystem for battery status monitoring. Connecting this
driver to the relevant IIO device requires registration of
the appropriate iio_map structure array by the IIO device
driver (usually from platform data). If specified the driver
will also make use of a gpio to provide interrupt driven
notification that the battery is fully charged.
In last version:
Addressed concerns raised by lars:
a. made the adc_bat per device.
b. get the IIO channel using hardcoded channel names.
c. Minor issues related to gpio_is_valid and some code
refactoring.
In V1:
Addressed concerns raised by Anton:
a. changed the struct name to gab(generic adc battery).
b. Added some functions to neaten the code.
c. Some minor coding guidelines changes.
d. Used the latest function introduce by lars:
iio_read_channel_processed to streamline the code.
In V2:
Addressed concerns by lars:
a. No need of allocating memory for channels.Make it array.
b. Code restructring, coding style and following kernel guidelines changes
suggested by him.
In V3:
Addressed conerns by Anton:
a. Added the copyright.
b. Coding guidelines changes suggested by him.
c. Added Makefile and Kconfig
Signed-off-by: anish kumar <anish198519851985@gmail.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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Fix below issues:
1. In the case of goto err_close, hid_hw_stop(hdev) is called twice. Fix it.
2. If fails to allocate MFD device name, we also need to free all
successfully allocated names in previous iterations.
3. In sensor_hub_remove(), Call hid_hw_close() before hid_hw_stop().
4. Adjust unnecessary change lines for hid_err.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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Current implementation of hid_hw_start() allows connect_mask to be 0.
Setting hdev->claimed = HID_CLAIMED_INPUT before calling hid_hw_start()
is not necessary. Remove it.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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TI LP8788 PMU provides regulators, battery charger, ADC,
RTC, backlight driver and current sinks.
This patch enables the LP8788 ADC functions.
The LP8788 ADC has several ADC input selection and supports 12bit resolution.
Internal operation of getting ADC is access to registers of LP8788.
The LP8788 ADC uses exported functions for accessing these registers.
(exported by LP8788 MFD device driver)
This driver supports IIO_CHAN_INFO_RAW and SCALE.
So the IIO consumer can calculate the value with raw and scale.
The unit of scale is micro.
(ADC Input Selection)
Voltage: battery voltage (MAX 5.0, 5.5 and 6.0V)
charger input voltage
four general ADC inputs
coin cell voltage
Current: battery charging current
Temperature: IC temperature
(The IIO map for the IIO consumer)
The ADC input is configurable in the platform side.
Even though this platform data is not defined,
the default IIO map is created for supporting the power supply driver.
The battery voltage and temperature are used inside this driver.
(History)
Patch v6.
(a) Fix scale value for each ADC input selection
Voltage and current type are mili unit and temperature is degree.
To calculate the IC temperature,
temp = raw * scaleint + (raw * scalepart)/ 1000000, scaleint is always 0.
= raw * 0.061050, raw: 0 ~ 4095
Then range of IC temperature(ADC result) is 0 ~ 250'C
(b) Reorganization of the IIO channel Spec
Remove address, scan_type and scan_index and rollback the datasheet name.
The reason why 'address' field is unnecessary is no relation with each channel.
Moreover, to get the raw ADC value, the address info is not only one register
but also several registers.
Therefore specific function(lp8788_get_adc_result) is called rather than
using one 'address' field.
(c) Fix coding style
Remove duplicated checking routine while unregistering the IIO map.
Fix code for space and parenthesis.
Patch v5.
Fix default consumer name as 'lp8788-charger'.
Add mutex for ADC read operation.
Reorganization on lp8788_adc_read_raw().
Patch v4.
Fix adc_raw function: support RAW and SCALE channel info.
Change LP8788 ADC platform data - iio map.
Enables the default IIO map.
Patch v3.
Fix wrong size of allocating iio private data.
Fix coding styles.
Patch v2.
Support RAW and SCALE interface for IIO consumer.
Clean up the iio channel spec macro.
Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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The ad7170/ad7171 have a software interface similar to the ad7780. They do not
have an external pin which allows to change the internal gain and the what is
used for the gain bit in the ad7780/ad7781 becomes part of the check pattern.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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Some designs hardwire the PDRST pin to always on. In this case there is no GPIO
to control the mode of the device, so make the GPIO optional. Since now all of
the the platform data fields are optional now, make the platform data as a whole
optional as well.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The errors which the driver tries to handle in the remove function are
non-critical, so we can just ignore them and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The errors which the driver tries to handle in the remove function are
non-critical, so we can just ignore them and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The error which the driver tries to handle in the remove function is
non-critical, so we can just ignore it and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The error which the driver tries to handle in the remove function is
non-critical, so we can just ignore it and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The error which the driver tries to handle in the remove function is
non-critical, so we can just ignore it and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The error which the driver tries to handle in the remove function is
non-critical, so we can just ignore it and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The error which the driver tries to handle in the remove function is
non-critical, so we can just ignore it and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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In the Linux device driver model the remove callback is not allowed to fail and
the device will be removed regardless of the return value of the remove
callback. So if we abort in the remove function and do not free all resources we
will create a resource leak. Also all kinds of undefined behaviour are expected
to happen since the IIO device is still there while its parent is already gone.
The error which the driver tries to handle in the remove function is
non-critical, so we can just ignore it and continue to free all resources and
remove the IIO device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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When the IIO consumer tries to get specific IIO channel,
few error cases can be happened.
(a) Memory allocation failure
(b) No matched ADC channel error
(c) Invalid input arguments
This patch enables cleaning up error handling in case of (a) and (b).
In error handling code,
(a): the reference count of the IIO device should be decreased.
(b): the allocated memory should be freed with restoring the reference count.
Therefore iio_deivce_put() is called in both cases.
This can be handled in the last error statement.
Additionally, integer variable is used for stating each error case explicitly.
Then, the error returns as ERR_PTR() with this value.
Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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The reference count of the IIO device is increased if the IIO map has
matched consumer name.
After then, it tries to allocate the iio_channel which is used by the consumer.
If it fails to allocate memory, the reference count should be decreased.
This patch enables restoring the reference count of the IIO device.
Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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