With various drivers wanting to inject idle time; we get people
calling idle routines outside of the idle loop proper.

Therefore we need to be extra careful about not missing
TIF_NEED_RESCHED -> PREEMPT_NEED_RESCHED propagations.

While looking at this, I also realized there's a small window in the
existing idle loop where we can miss TIF_NEED_RESCHED; when it hits
right after the tif_need_resched() test at the end of the loop but
right before the need_resched() test at the start of the loop.

So move preempt_fold_need_resched() out of the loop where we're
guaranteed to have TIF_NEED_RESCHED set.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-x9jgh45oeayzajz2mjt0y7d6@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently local_bh_disable() is out-of-line for no apparent reason.
So inline it to save a few cycles on call/return nonsense, the
function body is a single add on x86 (a few loads and store extra on
load/store archs).

Also expose two new local_bh functions:

  __local_bh_{dis,en}able_ip(unsigned long ip, unsigned int cnt);

Which implement the actual local_bh_{dis,en}able() behaviour.

The next patch uses the exposed @cnt argument to optimize bh lock
functions.

With build fixes from Jacob Pan.

Cc: rjw@rjwysocki.net
Cc: rui.zhang@intel.com
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: hpa@zytor.com
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: lenb@kernel.org
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131119151338.GF3694@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

In order to avoid the runtime condition and variable load turn
sched_clock_stable into a static_key.

Also provide a shorter implementation of local_clock() and
cpu_clock(int) when sched_clock_stable==1.

                        MAINLINE   PRE       POST

    sched_clock_stable: 1          1         1
    (cold) sched_clock: 329841     221876    215295
    (cold) local_clock: 301773     234692    220773
    (warm) sched_clock: 38375      25602     25659
    (warm) local_clock: 100371     33265     27242
    (warm) rdtsc:       27340      24214     24208
    sched_clock_stable: 0          0         0
    (cold) sched_clock: 382634     235941    237019
    (cold) local_clock: 396890     297017    294819
    (warm) sched_clock: 38194      25233     25609
    (warm) local_clock: 143452     71234     71232
    (warm) rdtsc:       27345      24245     24243
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-eummbdechzz37mwmpags1gjr@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Discourage drivers/modules to be creative with preemption.

Sadly all is implemented in macros and inline so if they want to do
evil they still can, but at least try and discourage some.
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: rui.zhang@intel.com
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: hpa@zytor.com
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-fn7h6vu8wtgxk0ih402qcijx@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently all _bh_ lock functions do two preempt_count operations:

  local_bh_disable();
  preempt_disable();

and for the unlock:

  preempt_enable_no_resched();
  local_bh_enable();

Since its a waste of perfectly good cycles to modify the same variable
twice when you can do it in one go; use the new
__local_bh_{dis,en}able_ip() functions that allow us to provide a
preempt_count value to add/sub.

So define SOFTIRQ_LOCK_OFFSET as the offset a _bh_ lock needs to
add/sub to be done in one go.

As a bonus it gets rid of the preempt_enable_no_resched() usage.

This reduces a 1000 loops of:

  spin_lock_bh(&bh_lock);
  spin_unlock_bh(&bh_lock);

from 53596 cycles to 51995 cycles. I didn't do enough measurements to
say for absolute sure that the result is significant but the the few
runs I did for each suggest it is so.
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: hpa@zytor.com
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: rui.zhang@intel.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20131119151338.GF3694@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Remove the deadline specific sysctls for now. The problem with them is
that the interaction with the exisiting rt knobs is nearly impossible
to get right.

The current (as per before this patch) situation is that the rt and dl
bandwidth is completely separate and we enforce rt+dl < 100%. This is
undesirable because this means that the rt default of 95% leaves us
hardly any room, even though dl tasks are saver than rt tasks.

Another proposed solution was (a discarted patch) to have the dl
bandwidth be a fraction of the rt bandwidth. This is highly
confusing imo.

Furthermore neither proposal is consistent with the situation we
actually want; which is rt tasks ran from a dl server. In which case
the rt bandwidth is a direct subset of dl.

So whichever way we go, the introduction of dl controls at this point
is painful. Therefore remove them and instead share the rt budget.

This means that for now the rt knobs are used for dl admission control
and the dl runtime is accounted against the rt runtime. I realise that
this isn't entirely desirable either; but whatever we do we appear to
need to change the interface later, so better have a small interface
for now.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-zpyqbqds1r0vyxtxza1e7rdc@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

In order of deadline scheduling to be effective and useful, it is
important that some method of having the allocation of the available
CPU bandwidth to tasks and task groups under control.
This is usually called "admission control" and if it is not performed
at all, no guarantee can be given on the actual scheduling of the
-deadline tasks.

Since when RT-throttling has been introduced each task group have a
bandwidth associated to itself, calculated as a certain amount of
runtime over a period. Moreover, to make it possible to manipulate
such bandwidth, readable/writable controls have been added to both
procfs (for system wide settings) and cgroupfs (for per-group
settings).

Therefore, the same interface is being used for controlling the
bandwidth distrubution to -deadline tasks and task groups, i.e.,
new controls but with similar names, equivalent meaning and with
the same usage paradigm are added.

However, more discussion is needed in order to figure out how
we want to manage SCHED_DEADLINE bandwidth at the task group level.
Therefore, this patch adds a less sophisticated, but actually
very sensible, mechanism to ensure that a certain utilization
cap is not overcome per each root_domain (the single rq for !SMP
configurations).

Another main difference between deadline bandwidth management and
RT-throttling is that -deadline tasks have bandwidth on their own
(while -rt ones doesn't!), and thus we don't need an higher level
throttling mechanism to enforce the desired bandwidth.

This patch, therefore:

 - adds system wide deadline bandwidth management by means of:
    * /proc/sys/kernel/sched_dl_runtime_us,
    * /proc/sys/kernel/sched_dl_period_us,
   that determine (i.e., runtime / period) the total bandwidth
   available on each CPU of each root_domain for -deadline tasks;

 - couples the RT and deadline bandwidth management, i.e., enforces
   that the sum of how much bandwidth is being devoted to -rt
   -deadline tasks to stay below 100%.

This means that, for a root_domain comprising M CPUs, -deadline tasks
can be created until the sum of their bandwidths stay below:

    M * (sched_dl_runtime_us / sched_dl_period_us)

It is also possible to disable this bandwidth management logic, and
be thus free of oversubscribing the system up to any arbitrary level.
Signed-off-by: NDario Faggioli <raistlin@linux.it>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-12-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Some method to deal with rt-mutexes and make sched_dl interact with
the current PI-coded is needed, raising all but trivial issues, that
needs (according to us) to be solved with some restructuring of
the pi-code (i.e., going toward a proxy execution-ish implementation).

This is under development, in the meanwhile, as a temporary solution,
what this commits does is:

 - ensure a pi-lock owner with waiters is never throttled down. Instead,
   when it runs out of runtime, it immediately gets replenished and it's
   deadline is postponed;

 - the scheduling parameters (relative deadline and default runtime)
   used for that replenishments --during the whole period it holds the
   pi-lock-- are the ones of the waiting task with earliest deadline.

Acting this way, we provide some kind of boosting to the lock-owner,
still by using the existing (actually, slightly modified by the previous
commit) pi-architecture.

We would stress the fact that this is only a surely needed, all but
clean solution to the problem. In the end it's only a way to re-start
discussion within the community. So, as always, comments, ideas, rants,
etc.. are welcome! :-)
Signed-off-by: NDario Faggioli <raistlin@linux.it>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
[ Added !RT_MUTEXES build fix. ]
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-11-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Turn the pi-chains from plist to rb-tree, in the rt_mutex code,
and provide a proper comparison function for -deadline and
-priority tasks.

This is done mainly because:
 - classical prio field of the plist is just an int, which might
   not be enough for representing a deadline;
 - manipulating such a list would become O(nr_deadline_tasks),
   which might be to much, as the number of -deadline task increases.

Therefore, an rb-tree is used, and tasks are queued in it according
to the following logic:
 - among two -priority (i.e., SCHED_BATCH/OTHER/RR/FIFO) tasks, the
   one with the higher (lower, actually!) prio wins;
 - among a -priority and a -deadline task, the latter always wins;
 - among two -deadline tasks, the one with the earliest deadline
   wins.

Queueing and dequeueing functions are changed accordingly, for both
the list of a task's pi-waiters and the list of tasks blocked on
a pi-lock.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NDario Faggioli <raistlin@linux.it>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-again-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-10-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Make it possible to specify a period (different or equal than
deadline) for -deadline tasks. Relative deadlines (D_i) are used on
task arrivals to generate new scheduling (absolute) deadlines as "d =
t + D_i", and periods (P_i) to postpone the scheduling deadlines as "d
= d + P_i" when the budget is zero.

This is in general useful to model (and schedule) tasks that have slow
activation rates (long periods), but have to be scheduled soon once
activated (short deadlines).
Signed-off-by: NHarald Gustafsson <harald.gustafsson@ericsson.com>
Signed-off-by: NDario Faggioli <raistlin@linux.it>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-7-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Introduces data structures relevant for implementing dynamic
migration of -deadline tasks and the logic for checking if
runqueues are overloaded with -deadline tasks and for choosing
where a task should migrate, when it is the case.

Adds also dynamic migrations to SCHED_DEADLINE, so that tasks can
be moved among CPUs when necessary. It is also possible to bind a
task to a (set of) CPU(s), thus restricting its capability of
migrating, or forbidding migrations at all.

The very same approach used in sched_rt is utilised:
 - -deadline tasks are kept into CPU-specific runqueues,
 - -deadline tasks are migrated among runqueues to achieve the
   following:
    * on an M-CPU system the M earliest deadline ready tasks
      are always running;
    * affinity/cpusets settings of all the -deadline tasks is
      always respected.

Therefore, this very special form of "load balancing" is done with
an active method, i.e., the scheduler pushes or pulls tasks between
runqueues when they are woken up and/or (de)scheduled.
IOW, every time a preemption occurs, the descheduled task might be sent
to some other CPU (depending on its deadline) to continue executing
(push). On the other hand, every time a CPU becomes idle, it might pull
the second earliest deadline ready task from some other CPU.

To enforce this, a pull operation is always attempted before taking any
scheduling decision (pre_schedule()), as well as a push one after each
scheduling decision (post_schedule()). In addition, when a task arrives
or wakes up, the best CPU where to resume it is selected taking into
account its affinity mask, the system topology, but also its deadline.
E.g., from the scheduling point of view, the best CPU where to wake
up (and also where to push) a task is the one which is running the task
with the latest deadline among the M executing ones.

In order to facilitate these decisions, per-runqueue "caching" of the
deadlines of the currently running and of the first ready task is used.
Queued but not running tasks are also parked in another rb-tree to
speed-up pushes.
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NDario Faggioli <raistlin@linux.it>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-5-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Introduces the data structures, constants and symbols needed for
SCHED_DEADLINE implementation.

Core data structure of SCHED_DEADLINE are defined, along with their
initializers. Hooks for checking if a task belong to the new policy
are also added where they are needed.

Adds a scheduling class, in sched/dl.c and a new policy called
SCHED_DEADLINE. It is an implementation of the Earliest Deadline
First (EDF) scheduling algorithm, augmented with a mechanism (called
Constant Bandwidth Server, CBS) that makes it possible to isolate
the behaviour of tasks between each other.

The typical -deadline task will be made up of a computation phase
(instance) which is activated on a periodic or sporadic fashion. The
expected (maximum) duration of such computation is called the task's
runtime; the time interval by which each instance need to be completed
is called the task's relative deadline. The task's absolute deadline
is dynamically calculated as the time instant a task (better, an
instance) activates plus the relative deadline.

The EDF algorithms selects the task with the smallest absolute
deadline as the one to be executed first, while the CBS ensures each
task to run for at most its runtime every (relative) deadline
length time interval, avoiding any interference between different
tasks (bandwidth isolation).
Thanks to this feature, also tasks that do not strictly comply with
the computational model sketched above can effectively use the new
policy.

To summarize, this patch:
 - introduces the data structures, constants and symbols needed;
 - implements the core logic of the scheduling algorithm in the new
   scheduling class file;
 - provides all the glue code between the new scheduling class and
   the core scheduler and refines the interactions between sched/dl
   and the other existing scheduling classes.
Signed-off-by: NDario Faggioli <raistlin@linux.it>
Signed-off-by: NMichael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: NFabio Checconi <fchecconi@gmail.com>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-4-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add the syscalls needed for supporting scheduling algorithms
with extended scheduling parameters (e.g., SCHED_DEADLINE).

In general, it makes possible to specify a periodic/sporadic task,
that executes for a given amount of runtime at each instance, and is
scheduled according to the urgency of their own timing constraints,
i.e.:

 - a (maximum/typical) instance execution time,
 - a minimum interval between consecutive instances,
 - a time constraint by which each instance must be completed.

Thus, both the data structure that holds the scheduling parameters of
the tasks and the system calls dealing with it must be extended.
Unfortunately, modifying the existing struct sched_param would break
the ABI and result in potentially serious compatibility issues with
legacy binaries.

For these reasons, this patch:

 - defines the new struct sched_attr, containing all the fields
   that are necessary for specifying a task in the computational
   model described above;

 - defines and implements the new scheduling related syscalls that
   manipulate it, i.e., sched_setattr() and sched_getattr().

Syscalls are introduced for x86 (32 and 64 bits) and ARM only, as a
proof of concept and for developing and testing purposes. Making them
available on other architectures is straightforward.

Since no "user" for these new parameters is introduced in this patch,
the implementation of the new system calls is just identical to their
already existing counterpart. Future patches that implement scheduling
policies able to exploit the new data structure must also take care of
modifying the sched_*attr() calls accordingly with their own purposes.
Signed-off-by: NDario Faggioli <raistlin@linux.it>
[ Rewrote to use sched_attr. ]
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
[ Removed sched_setscheduler2() for now. ]
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-3-git-send-email-juri.lelli@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently, the tx queue were selected implicitly in ndo_dfwd_start_xmit(). The
will cause several issues:

- NETIF_F_LLTX were removed for macvlan, so txq lock were done for macvlan
  instead of lower device which misses the necessary txq synchronization for
  lower device such as txq stopping or frozen required by dev watchdog or
  control path.
- dev_hard_start_xmit() was called with NULL txq which bypasses the net device
  watchdog.
- dev_hard_start_xmit() does not check txq everywhere which will lead a crash
  when tso is disabled for lower device.

Fix this by explicitly introducing a new param for .ndo_select_queue() for just
selecting queues in the case of l2 forwarding offload. netdev_pick_tx() was also
extended to accept this parameter and dev_queue_xmit_accel() was used to do l2
forwarding transmission.

With this fixes, NETIF_F_LLTX could be preserved for macvlan and there's no need
to check txq against NULL in dev_hard_start_xmit(). Also there's no need to keep
a dedicated ndo_dfwd_start_xmit() and we can just reuse the code of
dev_queue_xmit() to do the transmission.

In the future, it was also required for macvtap l2 forwarding support since it
provides a necessary synchronization method.

Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: e1000-devel@lists.sourceforge.net
Signed-off-by: NJason Wang <jasowang@redhat.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

VM to VM GSO traffic is broken if it goes through VXLAN or GRE
tunnel and the physical NIC on the host supports hardware VXLAN/GRE
GSO offload (e.g. bnx2x and next-gen mlx4).

Two issues -
(VXLAN) VM traffic has SKB_GSO_DODGY and SKB_GSO_UDP_TUNNEL with
SKB_GSO_TCP/UDP set depending on the inner protocol. GSO header
integrity check fails in udp4_ufo_fragment if inner protocol is
TCP. Also gso_segs is calculated incorrectly using skb->len that
includes tunnel header. Fix: robust check should only be applied
to the inner packet.

(VXLAN & GRE) Once GSO header integrity check passes, NULL segs
is returned and the original skb is sent to hardware. However the
tunnel header is already pulled. Fix: tunnel header needs to be
restored so that hardware can perform GSO properly on the original
packet.
Signed-off-by: NWei-Chun Chao <weichunc@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The SCTP outqueue structure maintains a data chunks
that are pending transmission, the list of chunks that
are pending a retransmission and a length of data in
flight.  It also tries to keep the emtpy state so that
it can performe shutdown sequence or notify user.

The problem is that the empy state is inconsistently
tracked.  It is possible to completely drain the queue
without sending anything when using PR-SCTP.  In this
case, the empty state will not be correctly state as
report by Jamal Hadi Salim <jhs@mojatatu.com>.  This
can cause an association to be perminantly stuck in the
SHUTDOWN_PENDING state.

Additionally, SCTP is incredibly inefficient when setting
the empty state.  Even though all the data is availaible
in the outqueue structure, we ignore it and walk a list
of trasnports.

In the end, we can completely remove the extra empty
state and figure out if the queue is empty by looking
at 3 things:  length of pending data, length of in-flight
data, and exisiting of retransmit data.  All of these
are already in the strucutre.
Reported-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NVlad Yasevich <vyasevich@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Tested-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Function llc_conn_ac_inc_vr_by_1() evaluates via macro
PDU_GET_NEXT_Vr() into ...

  llc_sk(sk)->vR = ++llc_sk(sk)->vR & 0xffffffffffffff7f

... but the order in which the side effects take place is
undefined because there is no intervening sequence point.

As llc_sk(sk)->vR is written in llc_sk(sk)->vR (assignment
left-hand side) and written in ++llc_sk(sk)->vR & 0xffffffffffffff7f
this might possibly yield undefined behavior.

The final value of llc_sk(sk)->vR is ambiguous, because,
depending on the order of expression evaluation, the
increment may occur before, after, or interleaved with
the assignment. In C, evaluating such an expression yields
undefined behavior.

Since we're doing the increment via PDU_GET_NEXT_Vr() macro
and the only place it is being used is from
llc_conn_ac_inc_vr_by_1(), in order to increment vR by 1
with a follow-up optimized modulo, rewrite the expression
into ((vR + 1) & CONST) in order to fix this.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the vlan code detects that the real device can do TX VLAN offloads
in hardware, it tries to arrange for the real device's header_ops to
be invoked directly.

But it does so illegally, by simply hooking the real device's
header_ops up to the VLAN device.

This doesn't work because we will end up invoking a set of header_ops
routines which expect a device type which matches the real device, but
will see a VLAN device instead.

Fix this by providing a pass-thru set of header_ops which will arrange
to pass the proper real device instead.

To facilitate this add a dev_rebuild_header().  There are
implementations which provide a ->cache and ->create but not a
->rebuild (f.e. PLIP).  So we need a helper function just like
dev_hard_header() to avoid crashes.

Use this helper in the one existing place where the
header_ops->rebuild was being invoked, the neighbour code.

With lots of help from Florian Westphal.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The changes in the ACPI-based PCI hotplug (ACPIPHP) subsystem made
during the 3.12 development cycle uncovered a problem with VGA
switcheroo that on some systems, when the device-specific method
(ATPX in the radeon case, _DSM in the nouveau case) is used to turn
off the discrete graphics, the BIOS generates ACPI hotplug events for
that device and those events cause ACPIPHP to attempt to remove the
device from the system (they are events for a device that was present
previously and is not present any more, so that's what should be done
according to the spec).  Then, the system stops functioning correctly.

Since the hotplug events in question were simply silently ignored
previously, the least intrusive way to address that problem is to
make ACPIPHP ignore them again.  For this purpose, introduce a new
ACPI device flag, no_hotplug, and modify ACPIPHP to ignore hotplug
events for PCI devices whose ACPI companions have that flag set.
Next, make the radeon and nouveau switcheroo detection code set the
no_hotplug flag for the discrete graphics' ACPI companion.

Fixes: bbd34fcd (ACPI / hotplug / PCI: Register all devices under the given bridge)
References: https://bugzilla.kernel.org/show_bug.cgi?id=61891
References: https://bugzilla.kernel.org/show_bug.cgi?id=64891Reported-and-tested-by: NMike Lothian <mike@fireburn.co.uk>
Reported-and-tested-by: <madcatx@atlas.cz>
Reported-and-tested-by: NJoaquín Aramendía <samsagax@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+

We've seen so many instances of people invoking skb_tx_timestamp()
after the device already has been given the packet, that it's worth
being a little bit more verbose and explicit in this comment.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 2171364d ("powerpc: Add HWCAP2 aux entry") introduced a new
AT_ auxv entry type AT_HWCAP2 but failed to update AT_VECTOR_SIZE_BASE
accordingly.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: 2171364d (powerpc: Add HWCAP2 aux entry)
Cc: stable@vger.kernel.org
Acked-by: NMichael Neuling <michael@neuling.org>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This will allow userspace to correctly program the PA_SC_RASTER_CONFIG
register, so it can be considered a fix.
Signed-off-by: NMarek Olšák <marek.olsak@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Fixes rendering corruption due to incorrect
gfx configuration.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=63599Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

The arbitrary restriction on page counts offered by the core
migrate_page_move_mapping() code results in rather suspicious looking
fiddling with page reference counts in the aio_migratepage() operation.
To fix this, make migrate_page_move_mapping() take an extra_count parameter
that allows aio to tell the code about its own reference count on the page
being migrated.

While cleaning up aio_migratepage(), make it validate that the old page
being passed in is actually what aio_migratepage() expects to prevent
misbehaviour in the case of races.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>

Some pstore backing devices use on board flash as persistent
storage. These have limited numbers of write cycles so it
is a poor idea to use them from high frequency operations.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In struct page we have enough space to fit long-size page->ptl there,
but we use dynamically-allocated page->ptl if size(spinlock_t) is larger
than sizeof(int).

It hurts 64-bit architectures with CONFIG_GENERIC_LOCKBREAK, where
sizeof(spinlock_t) == 8, but it easily fits into struct page.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Sasha Levin found a NULL pointer dereference that is due to a missing
page table lock, which in turn is due to the pmd entry in question being
a transparent huge-table entry.

The code - introduced in commit 1998cc04 ("mm: make
madvise(MADV_WILLNEED) support swap file prefetch") - correctly checks
for this situation using pmd_none_or_trans_huge_or_clear_bad(), but it
turns out that that function doesn't work correctly.

pmd_none_or_trans_huge_or_clear_bad() expected that pmd_bad() would
trigger if the transparent hugepage bit was set, but it doesn't do that
if pmd_numa() is also set. Note that the NUMA bit only gets set on real
NUMA machines, so people trying to reproduce this on most normal
development systems would never actually trigger this.

Fix it by removing the very subtle (and subtly incorrect) expectation,
and instead just checking pmd_trans_huge() explicitly.
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Acked-by: NAndrea Arcangeli <aarcange@redhat.com>
[ Additionally remove the now stale test for pmd_trans_huge() inside the
  pmd_bad() case - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch allows FILEIO to update hw_max_sectors based on the current
max_bytes_per_io.  This is required because vfs_[writev,readv]() can accept
a maximum of 2048 iovecs per call, so the enforced hw_max_sectors really
needs to be calculated based on block_size.

This addresses a >= v3.5 bug where block_size=512 was rejecting > 1M
sized I/O requests, because FD_MAX_SECTORS was hardcoded to 2048 for
the block_size=4096 case.

(v2: Use max_bytes_per_io instead of ->update_hw_max_sectors)
Reported-by: NHenrik Goldman <hg@x-formation.com>
Cc: <stable@vger.kernel.org> #3.5+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

According to documentation on barriers, stores issued before a LOCK can
complete after the lock implying that it's possible tlb_flush_pending
can be visible after a page table update.  As per revised documentation,
this patch adds a smp_mb__before_spinlock to guarantee the correct
ordering.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are a few subtle races, between change_protection_range (used by
mprotect and change_prot_numa) on one side, and NUMA page migration and
compaction on the other side.

The basic race is that there is a time window between when the PTE gets
made non-present (PROT_NONE or NUMA), and the TLB is flushed.

During that time, a CPU may continue writing to the page.

This is fine most of the time, however compaction or the NUMA migration
code may come in, and migrate the page away.

When that happens, the CPU may continue writing, through the cached
translation, to what is no longer the current memory location of the
process.

This only affects x86, which has a somewhat optimistic pte_accessible.
All other architectures appear to be safe, and will either always flush,
or flush whenever there is a valid mapping, even with no permissions
(SPARC).

The basic race looks like this:

CPU A			CPU B			CPU C

						load TLB entry
make entry PTE/PMD_NUMA
			fault on entry
						read/write old page
			start migrating page
			change PTE/PMD to new page
						read/write old page [*]
flush TLB
						reload TLB from new entry
						read/write new page
						lose data

[*] the old page may belong to a new user at this point!

The obvious fix is to flush remote TLB entries, by making sure that
pte_accessible aware of the fact that PROT_NONE and PROT_NUMA memory may
still be accessible if there is a TLB flush pending for the mm.

This should fix both NUMA migration and compaction.

[mgorman@suse.de: fix build]
Signed-off-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NMel Gorman <mgorman@suse.de>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

do_huge_pmd_numa_page() handles the case where there is parallel THP
migration.  However, by the time it is checked the NUMA hinting
information has already been disrupted.  This patch adds an earlier
check with some helpers.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 1b3a5d02 ("reboot: move arch/x86 reboot= handling to generic
kernel") moved reboot= handling to generic code.  In the process it also
removed the code in native_machine_shutdown() which are moving reboot
process to reboot_cpu/cpu0.

I guess that thought must have been that all reboot paths are calling
migrate_to_reboot_cpu(), so we don't need this special handling.  But
kexec reboot path (kernel_kexec()) is not calling
migrate_to_reboot_cpu() so above change broke kexec.  Now reboot can
happen on non-boot cpu and when INIT is sent in second kerneo to bring
up BP, it brings down the machine.

So start calling migrate_to_reboot_cpu() in kexec reboot path to avoid
this problem.

Bisected by WANG Chao.
Reported-by: NMatthew Whitehead <mwhitehe@redhat.com>
Reported-by: NDave Young <dyoung@redhat.com>
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Tested-by: NBaoquan He <bhe@redhat.com>
Tested-by: NWANG Chao <chaowang@redhat.com>
Acked-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ipgre_header_parse() needs to parse the tunnel's ip header and it
uses mac_header to locate the iphdr. This got broken when gre tunneling
was refactored as mac_header is no longer updated to point to iphdr.
Introduce skb_pop_mac_header() helper to do the mac_header assignment
and use it in ipgre_rcv() to fix msg_name parsing.

Bug introduced in commit c5441932 (GRE: Refactor GRE tunneling code.)

Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: NTimo Teräs <timo.teras@iki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is useful to be able to walk all upper devices when bringing
a device online where the RTNL lock is held. In this case it
is safe to walk the all_adj_list because the RTNL lock is used
to protect the write side as well.

This patch adds a check to see if the rtnl lock is held before
throwing a warning in netdev_all_upper_get_next_dev_rcu().

Also because we now have a call site for lockdep_rtnl_is_held()
outside COFIG_LOCK_PROVING an inline definition returning 1 is
needed. Similar to the rcu_read_lock_is_held().

Fixes: 2a47fa45 ("ixgbe: enable l2 forwarding acceleration for macvlans")
CC: Veaceslav Falico <vfalico@redhat.com>
Reported-by: NYuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Tested-by: NPhil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

commit 887c290e (sched/numa: Decide whether to favour task or group weights
based on swap candidate relationships) drop the check against
sysctl_numa_balancing_settle_count, this patch remove the sysctl.
Signed-off-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: NMel Gorman <mgorman@suse.de>
Reviewed-by: NRik van Riel <riel@redhat.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Link: http://lkml.kernel.org/r/1386833006-6600-1-git-send-email-liwanp@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit fdfbbd07 ("perf: Add generic transaction flags")
added support for PERF_SAMPLE_TRANSACTION but forgot to add documentation
for the sample type to include/uapi/linux/perf_event.h
Signed-off-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1312131548450.10372@pianoman.cluster.toySigned-off-by: NIngo Molnar <mingo@kernel.org>

Certain drives cannot handle queued TRIM commands properly, even
though support is indicated in the IDENTIFY DEVICE buffer.  This patch
allows for disabling the commands for the affected drives and apply it
to the Micron/Crucial M500 SSDs which exhibit incorrect protocol
behavior when issued queued TRIM commands, which could lead to silent
data corruption.

tj: Merged two unnecessarily split patches and made minor edits
    including shortening horkage name.
Signed-off-by: NMarc Carino <marc.ceeeee@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/g/1387246554-7311-1-git-send-email-marc.ceeeee@gmail.com
Cc: stable@vger.kernel.org # 3.12+

Userspace input buffer is not modified by kernel, so it can be 'const'.

This is also a prerequisite to remove the implicit cast
from INIT_UDATA().

Link: http://marc.info/?i=cover.1386798254.git.ydroneaud@opteya.com>
Signed-off-by: NYann Droneaud <ydroneaud@opteya.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Some devices with support for mobile networks may have buttons for
enabling/disabling such connection. An example can be Linksys router 54G3G.
We already have KEY_BLUETOOTH, KEY_WLAN and KEY_UWB so it makes sense to
add KEY_WWAN as well.  As we already have KEY_WIMAX, use it's value for
KEY_WWAN and make it an alias.
Signed-off-by: NRafał Miłecki <zajec5@gmail.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

On ARM (32 bits and 64 bits), the double-word is 8-bytes aligned. This will
result on different structure from Xen and Linux repositories.

As Linux is using __packed__ attribute, it must have a 4-bytes padding before
each "id" field.

This change breaks guest block support with older kernel. IMHO, it's acceptable
because Xen on ARM is still on Tech Preview and the hypercall ABI is not yet
freezed.

Only one architecture (x86_32) doesn't have 64-bit ABI for the block interface.
Don't add padding if Linux is compiled for this architecture.
Signed-off-by: NJulien Grall <julien.grall@linaro.org>
Acked-by: NRoger Pau Monne <roger.pau@citrix.com>
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
[I had asked for confirmation that it did not break x86 and Ian went
beyound the call of duty to confirm it. Also a internal regression
bucket with 32/64 dom0 with 32/64 domU (PV and HVM) confirmed no
regressions. ABI changes are a drag..]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>