It took me quite a while to understand how rwsem's count field
mainifested itself in different scenarios.

Add comments to provide a quick reference to the the rwsem's count
field for each scenario where readers and writers are contending
for the lock.

Hopefully it will be useful for future maintenance of the code and
for people to get up to speed on how the logic in the code works.
Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Paul E.McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1399060437.2970.146.camel@schen9-DESKSigned-off-by: NIngo Molnar <mingo@kernel.org>

Fuzzing a recent kernel with a large configuration hits the static
allocation limits and disables lockdep.

This patch doubles the limits.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389208906-24338-1-git-send-email-sasha.levin@oracle.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Mostly scripted conversion of the smp_mb__* barriers.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Update the documentation to reflect the change of barrier primitives.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/n/tip-xslfehiga1twbk5uk94rij1e@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Xtensa SMP has compare-and-swap which is fully serializing, therefore
its exising smp_mb__{before,after}_clear_bit() appear unduly heavy.

Implement the new barriers as barrier().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-e9rqjxr1m1ejsob9p433kmji@git.kernel.org
Cc: Chris Zankel <chris@zankel.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

x86 is strongly ordered and all its atomic ops imply a full barrier.

Implement the two new primitives as the old ones were.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-knswsr5mldkr0w1lrdxvc81w@git.kernel.org
Cc: Dave Jones <davej@redhat.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Implement the new smp_mb__* ops as per the old ones.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Link: http://lkml.kernel.org/n/tip-euuabnf5a3u23fy4fq8m3jcg@git.kernel.org
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

sparc32: fully relies on asm-generic/barrier.h and thus can use its
	 implementation.

sparc64: is strongly ordered and its atomic ops imply a full barrier,
	 implement the new primitives using barrier().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/n/tip-2cla9ubpd8chrntnm7e4zdt4@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

SH can use the asm-generic/barrier.h implementation since that uses
smp_mb().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-2z962by2ppzcd984ybw2mwdw@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

score fully relies on asm-generic/barrier.h, so it can use its default
implementation.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NLennox Wu <lennox.wu@gmail.com>
Link: http://lkml.kernel.org/n/tip-4mv9svf28lnotjpfuza8urh8@git.kernel.org
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

As per the existing implementation; implement the new one using
smp_mb().

AFAICT the s390 compare-and-swap does imply a barrier, however there
are some immediate ops that seem to be singly-copy atomic and do not
imply a barrier. One such is the "ni" op (which would be
and-immediate) which is used for the constant clear_bit
implementation. Therefore s390 needs full barriers for the
{before,after} atomic ops.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-kme5dz5hcobpnufnnkh1ech2@git.kernel.org
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux390@de.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Powerpc allows reordering over its ll/sc implementation. Implement the
two new barriers as appropriate.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-gg2ffgq32sjgy9b8lj6m3hsc@git.kernel.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

parisc fully relies on asm-generic/barrier.h, therefore its smp_mb()
is barrier and the default implementation suffices.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-mxs4aubiyesi79v8xx53093q@git.kernel.org
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Openrisc fully relies on asm-generic/barrier.h and therefore its
smp_mb() is barrier().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-sxgxgqag9tond4kji07d22oh@git.kernel.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux@lists.openrisc.net
Signed-off-by: NIngo Molnar <mingo@kernel.org>

mn10300 fully relies on asm-generic/barrier.h and therefore its
smp_mb() is barrier(). We can use the default implementation.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-wotyeoj99h1dpojjeest2jbk@git.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-am33-list@redhat.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

MIPS is interesting and has hardware variants that reorder over ll/sc
as well as those that do not.

Implement the 2 new barrier functions as per the old barriers.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-9ph49jbae3hol9v721sbc2g6@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maciej W. Rozycki" <macro@codesourcery.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Implement the new barriers; as per the old versions the metag atomic
imply a full barrier.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-dqnyo215kq38wi4xcxnbpjw3@git.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

m68k uses asm-generic/barrier.h and its smp_mb() is barrier(),
therefore we can use the generic versions that use smp_mb().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-s5dvosrb7qhvpmtaffwfn0zg@git.kernel.org
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

M32r uses asm-generic/barrier.h and its smp_mb() is barrier();
therefore we can use the generic versions which default to smp_mb().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-wh6xljltyvmpy9t0bc80k1fy@git.kernel.org
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

ia64 atomic ops are full barriers; implement the new
smp_mb__{before,after}_atomic().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-hyp7yj68cmqz1nqbfpr541ca@git.kernel.org
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Hexagon uses asm-gemeric/barrier.h and its smp_mb() is barrier().
Therefore we can use the default implementation that uses smp_mb().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-87irqrrbgizeojjfdqhypud3@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-hexagon@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Because:

arch/frv/include/asm/smp.h:#error SMP not supported

smp_mb() is barrier() and we can use the default implementation that
uses smp_mb().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-n296g51yzdu5ru1vp7mccxmf@git.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Cris fully relies on asm-generic/barrier.h, therefore its smp_mb() is
barrier(), thus we can use the default implementation that uses
smp_mb().

(Include asm/system.h and asm/barrier.h to avoid header dependency hell.)
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-wvewbe8os3s1e4pt1cdotuee@git.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: linux-cris-kernel@axis.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

c6x doesn't have a barrier.h and completely relies on
asm-generic/barrier.h. Therefore its smp_mb() is barrier() and we can
use the default versions that are smp_mb().
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NMark Salter <msalter@redhat.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-kl53k3pyj0rbd80jq8ralpf3@git.kernel.org
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Blackfin's atomic primitives do not imply a full barrier as whitnessed
from its SMP smp_mb__{before,after}_clear_bit() implementations.

However since !SMP smp_mb() reduces to barrier() remove everything and
rely on the asm-generic/barrier.h implentation.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-1widdkdsb3c1titq8jez6g3g@git.kernel.org
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Miao <realmz6@gmail.com>
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

AVR32's mb() implementation is a compiler barrier(), therefore it all
doesn't matter, fully rely on whatever asm-generic/barrier.h
generates.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-8gow97a7mapmnec0pvf729pj@git.kernel.org
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

AARGH64 uses ll/sc primitives that do not imply any barriers for the
normal atomics, therefore smp_mb__{before,after} should be a full
barrier.

Since AARGH64 doesn't use asm-generic/barrier.h, add the required
definitions to its asm/barrier.h.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-8p5iclqgy78al33kck3ht7nr@git.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

ARM uses ll/sc primitives that do not imply barriers for all regular
atomic ops, therefore smp_mb__{before,after} need be a full barrier.

Since ARM doesn't use asm-generic/barrier.h include the required
definitions in its asm/barrier.h
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-yijo7sglsl7uusbp13upcuvo@git.kernel.org
Cc: Albin Tonnerre <albin.tonnerre@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The arc mb() implementation is a compiler barrier(), therefore it all
doesn't matter one way or the other. Simply remove the existing
definitions and use whatever is generated by the defaults.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-ua48a59wri3ybz1rz8i7uvbr@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The Alpha ll/sc primitives do not imply any sort of barrier; therefore
the smp_mb__{before,after} should be a full barrier. This is the
default from asm-generic/barrier.h and therefore just remove the
current definitions.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-iacwfd15lq3ta2v7jut747r7@git.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: linux-alpha@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Since the smp_mb__{before,after}*() ops are fundamentally dependent on
how an arch can implement atomics it doesn't make sense to have 3
variants of them. They must all be the same.

Furthermore, the 3 variants suggest they're only valid for those 3
atomic ops, while we have many more where they could be applied.

So move away from
smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}() and reduce the
interface to just the two: smp_mb__{before,after}_atomic().

This patch prepares the way by introducing default implementations in
asm-generic/barrier.h that default to a full barrier and providing
__deprecated inlines for the previous 6 barriers if they're not
provided by the arch.

This should allow for a mostly painless transition (lots of deprecated
warns in the interim).
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-wr59327qdyi9mbzn6x937s4e@git.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Chen, Gong" <gong.chen@linux.intel.com>
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Both already use asm-generic/barrier.h as per their
include/asm/Kbuild. Remove the stale files.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-c7vlkshl3tblim0o8z2p70kt@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-hexagon@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

IA64 doesn't actually have acquire/release barriers, its a lie!

Add a comment explaining this and fix up the bitop barriers.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-akevfh136um9dqvb1ohm55ca@git.kernel.org
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Pull parisc updates from Helge Deller:
 "There are two major changes in this patchset:

  The major fix is that the epoll_pwait() syscall for 32bit userspace
  was not using the compat wrapper on a 64bit kernel.

  Secondly we changed the value of SHMLBA from 4MB to PAGE_SIZE to
  reflect that we can actually mmap to any multiple of PAGE_SIZE.  The
  only thing which needs care is that shared mmaps need to be mapped at
  the same offset inside the 4MB cache window"

* 'parisc-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: fix epoll_pwait syscall on compat kernel
  parisc: change value of SHMLBA from 0x00400000 to PAGE_SIZE
  parisc: Replace __get_cpu_var uses for address calculation

Merge ipmi fixes from Corey Minyard:
 "Things collected since last kernel release.

  Some of these are pretty important.  The first three are bug fixes.
  The next two are to hopefully make everyone happy about allowing
  ACPI to be on all the time and not have IPMI have an effect on the
  system when not in use.  The last is a little cleanup"

* emailed patches from Corey Minyard <cminyard@mvista.com>:
  ipmi: boolify some things
  ipmi: Turn off all activity on an idle ipmi interface
  ipmi: Turn off default probing of interfaces
  ipmi: Reset the KCS timeout when starting error recovery
  ipmi: Fix a race restarting the timer
  Char: ipmi_bt_sm, fix infinite loop

Convert some ints to bools.
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The IPMI driver would wake up periodically looking for events and
watchdog pretimeouts.  If there is nothing waiting for these events,
it's really kind of pointless to be checking for them.  So modify the
driver so the message handler can pass down if it needs the lower layer
to be waiting for these.  Modify the system interface lower layer to
turn off all timer and thread activity if the upper layer doesn't need
anything and it is not currently handling messages.  And modify the
message handler to not restart the timer if its timer is not needed.

The timers and kthread will still be enabled if:
 - the SI interface is handling a message.
 - a user has enabled watching for events.
 - the IPMI watchdog timer is in use (since it uses pretimeouts).
 - the message handler is waiting on a remote response.
 - a user has registered to receive commands.

This mostly affects interfaces without interrupts.  Interfaces with
interrupts already don't use CPU in the system interface when the
interface is idle.
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The default probing can cause problems with some system, slow booting,
extra CPU usages, etc.  Turn it off by default and give a config option
to enable it.

From: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The OBF timer in KCS was not reset in one situation when error recovery
was started, resulting in an immediate timeout.
Reported-by: NBodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With recent changes it is possible for the timer handler to detect an
idle interface and not start the timer, but the thread to start an
operation at the same time.  The thread will not start the timer in that
instance, resulting in the timer not running.

Instead, move all timer operations under the lock and start the timer in
the thread if it detect non-idle and the timer is not already running.
Moving under locks allows the last timeout to be set in both the thread
and the timer.  'Timer is not running' means that the timer is not
pending and smi_timeout() is not running.  So we need a flag to detect
this correctly.

Also fix a few other timeout bugs: setting the last timeout when the
interrupt has to be disabled and the timer started, and setting the last
timeout in check_start_timer_thread possibly racing with the timer
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Signed-off-by: NBodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>