rcu: Export debug_init_rcu_head() and and debug_init_rcu_head()

Currently, call_rcu() relies on implicit allocation and initialization
for the debug-objects handling of RCU callbacks.  If you hammer the
kernel hard enough with Sasha's modified version of trinity, you can end
up with the sl*b allocators recursing into themselves via this implicit
call_rcu() allocation.

This commit therefore exports the debug_init_rcu_head() and
debug_rcu_head_free() functions, which permits the allocators to allocated
and pre-initialize the debug-objects information, so that there no longer
any need for call_rcu() to do that initialization, which in turn prevents
the recursion into the memory allocators.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Looks-good-to: Christoph Lameter <cl@linux.com>
rcu: Reduce overhead of cond_resched() checks for RCU

Commit ac1bea85781e (Make cond_resched() report RCU quiescent states)
fixed a problem where a CPU looping in the kernel with but one runnable
task would give RCU CPU stall warnings, even if the in-kernel loop
contained cond_resched() calls.  Unfortunately, in so doing, it introduced
performance regressions in Anton Blanchard's will-it-scale "open1" test.
The problem appears to be not so much the increased cond_resched() path
length as an increase in the rate at which grace periods complete, which
increased per-update grace-period overhead.

This commit takes a different approach to fixing this bug, mainly by
moving the RCU-visible quiescent state from cond_resched() to
rcu_note_context_switch(), and by further reducing the check to a
simple non-zero test of a single per-CPU variable.  However, this
approach requires that the force-quiescent-state processing send
resched IPIs to the offending CPUs.  These will be sent only once
the grace period has reached an age specified by the boot/sysfs
parameter rcutree.jiffies_till_sched_qs, or once the grace period
reaches an age halfway to the point at which RCU CPU stall warnings
will be emitted, whichever comes first.

Reported-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
[ paulmck: Made rcu_momentary_dyntick_idle() as suggested by the
  ktest build robot.  Also fixed smp_mb() comment as noted by
  Oleg Nesterov. ]

Merge with e552592e (Reduce overhead of cond_resched() checks for RCU)

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Merge branch 'urgent.2014.06.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent

Pull RCU fixes from Paul E. McKenney:

" This series includes the following:

   1.    Export a pair of debug-object interfaces for RCU that will
         allow the slab allocators to avoid a recursion bug located
         by Sasha Levin.  Strictly speaking, this is not a regression,
         but it would be good to enable the fix.

   2.    Address a serious performance regression on an open/close
         micro-benchmark located by Dave Hansen.  The offending commit
         is ac1bea85781e (Make cond_resched() report RCU quiescent states).  "

Signed-off-by: Ingo Molnar <mingo@kernel.org>
UBI: fix the volumes tree sorting criteria

Commig "604b592 UBI: fix rb_tree node comparison in add_map"
broke fastmap backward compatibility and older fastmap images
cannot be mounted anymore. The reason is that it changes the
volumes RB-tree sorting criteria. This patch fixes the problem.

Artem: re-write the commit message

Signed-off-by: Heiko Schocher <hs@denx.de>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
ARM: mvebu: fix SMP boot for Armada 38x and Armada 375 Z1 in big endian

The SMP boot on Armada 38x and Armada 375 Z1 is currently broken in
big-endian configurations, and this commit fixes it for both
platforms.

For Armada 375 Z1, the problem was in the
armada_375_smp_cpu1_enable_code part of the code that gets copied to
the Crypto SRAM as a work-around for an issue of the Z1 stepping. This
piece of code was not switching the CPU core to big-endian, and not
endian-swapping the value read from the Resume Address register (the
value is stored little-endian). Due to the introduction of the
conditional 'rev r1, r1' instruction, the offset between the 'ldr r0,
[pc, #4]' instruction and the value it was looking is different
between LE and BE configurations. To solve this, we instead use one
'adr' instruction followed by one 'ldr'.

For Armada 38x, the problem was simply that the CPU core was not
switched to big endian in the secondary CPU startup function.

This change was tested in LE and BE configurations on Armada 385,
Armada 375 Z1 and Armada 375 A0.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1404228186-21203-1-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
efi/arm64: efistub: remove local copy of linux_banner

The shared efistub code for ARM and arm64 contains a local copy of
linux_banner, allowing it to be referenced from separate executables
such as the ARM decompressor. However, this introduces a dependency on
generated header files, causing unnecessary rebuilds of the stub itself
and, in case of arm64, vmlinux which contains it.

On arm64, the copy is not actually needed since we can reference the
original symbol directly, and as it turns out, there may be better ways
to deal with this for ARM as well, so let's remove it from the shared
code. If it still needs to be reintroduced for ARM later, it should live
under arch/arm anyway and not in shared code.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
iommu/fsl: Fix PAMU window size check.

is_power_of_2 requires an unsigned long parameter which would
lead to truncation of 64 bit values on 32 bit architectures.

__ffs also expects an unsigned long parameter thus won't work
for 64 bit values on 32 bit architectures.

Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Tested-by: Emil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/fsl: Fix the device domain attach condition.

Store the domain information for the device, only if it's not already
attached to a domain.

Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/fsl: Fix the error condition during iommu group

Earlier PTR_ERR was being returned even if group was set to null.
Now, we explicitly set an ERR_PTR value in case the group  pointer is
NULL.

Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
tools/liblockdep: Fix comparison of a boolean value with a value of 2

Comparison of a boolean value (!__init_state) with a value of 2 (done)
as currently happens in the code is unlikely to succeed and causes
repeated initialization of the pthread function pointers.

Instead, remove boolean comparison so that we would initialize said
function pointers only once.

Ref: https://bugzilla.kernel.org/show_bug.cgi?id=76741
Cc: Jean Delvare <jdelvare@suse.de>
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Dianfang Zhang <zhangdianfang@huawei.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
tools/liblockdep: Remove debug print left over from development

Remove a debug print in init_preload() which was left over from
development and isn't usefull at all currently. It was also causing
false positive test results.

Reported-by: S. Lockwood-Childs <sjl@vctlabs.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
tools/liblockdep: Account for bitfield changes in lockdeps lock_acquire

Commit fb9edbe984 shortened held_lock->check from a 2-bit field
to a 1-bit field.

Make liblockdep compatible with the new definition by passing check=1
to lock_acquire() calls, rather than the old value check=2 (which
inadvertently disabled checks by overflowing to 0).

Without this fix, several of the test cases in liblockdep run_tests.sh
were failing.

Signed-off-by: S. Lockwood-Childs <sjl@vctlabs.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
alarmtimer: Fix bug where relative alarm timers were treated as absolute

Sharvil noticed with the posix timer_settime interface, using the
CLOCK_REALTIME_ALARM or CLOCK_BOOTTIME_ALARM clockid, if the users
tried to specify a relative time timer, it would incorrectly be
treated as absolute regardless of the state of the flags argument.

This patch corrects this, properly checking the absolute/relative flag,
as well as adds further error checking that no invalid flag bits are set.

Reported-by: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Cc: stable <stable@vger.kernel.org> #3.0+
Link: http://lkml.kernel.org/r/1404767171-6902-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
ARM: mvebu: Fix the operand list in the inline asm of armada_370_xp_pmsu_idle_enter

In the inline asm part of the function armada_370_xp_pmsu_idle_enter()
the input operand was used. The intent here was to let the compiler
choose this register so it could do the optimization it
needed.

However an input operand is not supposed to be modified by the inline
asm code. This can lead to improper generated instructions.

In some case generated instruction the compiler made the choice to
reuse the same register to store the return value. But in the assembly
part this register was modified, so it can lead to return an wrong
value.

The fix is to use a clobber. Thanks to this the compiler will know
that the value of this register will be modified.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1404483736-16938-1-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
ARM: mvebu: Fix coherency bus notifiers by using separate notifiers

Currently, the coherency fabric support registers two bus notifiers;
one for platform, one for pci bus types, with the same notifier block.
However, this is illegal and can cause serious issues: the notifier
block is also a link in the notifier list and cannot be inserted twice.

This commit fixes this by using different notifier blocks (with the same
notifier callback) to set the platform and pci bus types notifiers.

Fixes: b0063aad5dd8 ("ARM: mvebu: use hardware I/O coherency also for PCI devices")
Reported-by: Paolo Pisati <p.pisati@gmail.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Link: https://lkml.kernel.org/r/1404826657-6977-1-git-send-email-ezequiel.garcia@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
nfs: only show Posix ACLs in listxattr if actually present

The big ACL switched nfs to use generic_listxattr, which calls all existing
->list handlers.  Add a custom .listxattr implementation that only lists
the ACLs if they actually are present on the given inode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Philippe Troin <phil@fifi.org>
Tested-by: Philippe Troin <phil@fifi.org>
Fixes: 013cdf1088d7 (nfs: use generic posix ACL infrastructure ...)
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
irqchip: gic: Add support for cortex a7 compatible string

Patch 0a68214b "ARM: DT: Add binding for GIC virtualization extentions (VGIC)" added
the "arm,cortex-a7-gic" compatible string, but the corresponding IRQCHIP_DECLARE
was never added to the gic driver.

To let real Cortex-A7 SoCs use it, add the necessary declaration to the device driver.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lkml.kernel.org/r/1404388732-28890-1-git-send-email-matthias.bgg@gmail.com
Fixes: 0a68214b76ca ("ARM: DT: Add binding for GIC virtualization extentions (VGIC)")
Cc: <stable@vger.kernel.org> # v3.5+
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
RDMA/cxgb4: Fix skb_leak in reject_cr()

Based on origninal work by Steve Wise <swise@opengridcomputing.com>

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
RDMA/cxgb4: Clean up connection on ARP error

Based on origninal work by Steve Wise <swise@opengridcomputing.com>

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
RDMA/cxgb4: Initialize the device status page

The status page is mapped to user processes and allows sharing the
device state between the kernel and user processes.  This state isn't
getting initialized and thus intermittently causes problems.  Namely,
the user process can mistakenly think the user doorbell writes are
disabled which causes SQ work requests to never get fetched by HW.

Fixes: 05eb23893c2c ("cxgb4/iw_cxgb4: Doorbell Drop Avoidance Bug Fixes").
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Cc: <stable@vger.kernel.org> # v3.15
Signed-off-by: Roland Dreier <roland@purestorage.com>