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linux/kernel/spinlock.c
Heiko Carstens 892a7c67c1 locking: Allow arch-inlined spinlocks 
This allows an architecture to specify per lock variant if the
locking code should be kept out-of-line or inlined.

If an architecure wants out-of-line locking code no change is
needed. To force inlining of e.g. spin_lock() the line:

  #define __always_inline__spin_lock

needs to be added to arch/<...>/include/asm/spinlock.h

If CONFIG_DEBUG_SPINLOCK or CONFIG_GENERIC_LOCKBREAK are
defined the per architecture defines are (partly) ignored and
still out-of-line spinlock code will be generated.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Horst Hartmann <horsth@linux.vnet.ibm.com>
Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <20090831124418.375299024@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-31 18:08:50 +02:00

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/*
* Copyright (2004) Linus Torvalds
*
* Author: Zwane Mwaikambo <zwane@fsmlabs.com>
*
* Copyright (2004, 2005) Ingo Molnar
*
* This file contains the spinlock/rwlock implementations for the
* SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
*
* Note that some architectures have special knowledge about the
* stack frames of these functions in their profile_pc. If you
* change anything significant here that could change the stack
* frame contact the architecture maintainers.
*/
#include <linux/linkage.h>
#include <linux/preempt.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include <linux/module.h>
#ifndef _spin_trylock
int __lockfunc _spin_trylock(spinlock_t *lock)
{
return __spin_trylock(lock);
}
EXPORT_SYMBOL(_spin_trylock);
#endif
#ifndef _read_trylock
int __lockfunc _read_trylock(rwlock_t *lock)
{
return __read_trylock(lock);
}
EXPORT_SYMBOL(_read_trylock);
#endif
#ifndef _write_trylock
int __lockfunc _write_trylock(rwlock_t *lock)
{
return __write_trylock(lock);
}
EXPORT_SYMBOL(_write_trylock);
#endif
/*
* If lockdep is enabled then we use the non-preemption spin-ops
* even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
* not re-enabled during lock-acquire (which the preempt-spin-ops do):
*/
#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
#ifndef _read_lock
void __lockfunc _read_lock(rwlock_t *lock)
{
__read_lock(lock);
}
EXPORT_SYMBOL(_read_lock);
#endif
#ifndef _spin_lock_irqsave
unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
{
return __spin_lock_irqsave(lock);
}
EXPORT_SYMBOL(_spin_lock_irqsave);
#endif
#ifndef _spin_lock_irq
void __lockfunc _spin_lock_irq(spinlock_t *lock)
{
__spin_lock_irq(lock);
}
EXPORT_SYMBOL(_spin_lock_irq);
#endif
#ifndef _spin_lock_bh
void __lockfunc _spin_lock_bh(spinlock_t *lock)
{
__spin_lock_bh(lock);
}
EXPORT_SYMBOL(_spin_lock_bh);
#endif
#ifndef _read_lock_irqsave
unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
{
return __read_lock_irqsave(lock);
}
EXPORT_SYMBOL(_read_lock_irqsave);
#endif
#ifndef _read_lock_irq
void __lockfunc _read_lock_irq(rwlock_t *lock)
{
__read_lock_irq(lock);
}
EXPORT_SYMBOL(_read_lock_irq);
#endif
#ifndef _read_lock_bh
void __lockfunc _read_lock_bh(rwlock_t *lock)
{
__read_lock_bh(lock);
}
EXPORT_SYMBOL(_read_lock_bh);
#endif
#ifndef _write_lock_irqsave
unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
{
return __write_lock_irqsave(lock);
}
EXPORT_SYMBOL(_write_lock_irqsave);
#endif
#ifndef _write_lock_irq
void __lockfunc _write_lock_irq(rwlock_t *lock)
{
__write_lock_irq(lock);
}
EXPORT_SYMBOL(_write_lock_irq);
#endif
#ifndef _write_lock_bh
void __lockfunc _write_lock_bh(rwlock_t *lock)
{
__write_lock_bh(lock);
}
EXPORT_SYMBOL(_write_lock_bh);
#endif
#ifndef _spin_lock
void __lockfunc _spin_lock(spinlock_t *lock)
{
__spin_lock(lock);
}
EXPORT_SYMBOL(_spin_lock);
#endif
#ifndef _write_lock
void __lockfunc _write_lock(rwlock_t *lock)
{
__write_lock(lock);
}
EXPORT_SYMBOL(_write_lock);
#endif
#else /* CONFIG_PREEMPT: */
/*
* This could be a long-held lock. We both prepare to spin for a long
* time (making _this_ CPU preemptable if possible), and we also signal
* towards that other CPU that it should break the lock ASAP.
*
* (We do this in a function because inlining it would be excessive.)
*/
#define BUILD_LOCK_OPS(op, locktype) \
void __lockfunc _##op##_lock(locktype##_t *lock) \
{ \
for (;;) { \
preempt_disable(); \
if (likely(_raw_##op##_trylock(lock))) \
break; \
preempt_enable(); \
\
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!op##_can_lock(lock) && (lock)->break_lock) \
_raw_##op##_relax(&lock->raw_lock); \
} \
(lock)->break_lock = 0; \
} \
\
EXPORT_SYMBOL(_##op##_lock); \
\
unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \
{ \
unsigned long flags; \
\
for (;;) { \
preempt_disable(); \
local_irq_save(flags); \
if (likely(_raw_##op##_trylock(lock))) \
break; \
local_irq_restore(flags); \
preempt_enable(); \
\
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!op##_can_lock(lock) && (lock)->break_lock) \
_raw_##op##_relax(&lock->raw_lock); \
} \
(lock)->break_lock = 0; \
return flags; \
} \
\
EXPORT_SYMBOL(_##op##_lock_irqsave); \
\
void __lockfunc _##op##_lock_irq(locktype##_t *lock) \
{ \
_##op##_lock_irqsave(lock); \
} \
\
EXPORT_SYMBOL(_##op##_lock_irq); \
\
void __lockfunc _##op##_lock_bh(locktype##_t *lock) \
{ \
unsigned long flags; \
\
/* */ \
/* Careful: we must exclude softirqs too, hence the */ \
/* irq-disabling. We use the generic preemption-aware */ \
/* function: */ \
/**/ \
flags = _##op##_lock_irqsave(lock); \
local_bh_disable(); \
local_irq_restore(flags); \
} \
\
EXPORT_SYMBOL(_##op##_lock_bh)
/*
* Build preemption-friendly versions of the following
* lock-spinning functions:
*
* _[spin|read|write]_lock()
* _[spin|read|write]_lock_irq()
* _[spin|read|write]_lock_irqsave()
* _[spin|read|write]_lock_bh()
*/
BUILD_LOCK_OPS(spin, spinlock);
BUILD_LOCK_OPS(read, rwlock);
BUILD_LOCK_OPS(write, rwlock);
#endif /* CONFIG_PREEMPT */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass)
{
preempt_disable();
spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
}
EXPORT_SYMBOL(_spin_lock_nested);
unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock,
_raw_spin_lock_flags, &flags);
return flags;
}
EXPORT_SYMBOL(_spin_lock_irqsave_nested);
void __lockfunc _spin_lock_nest_lock(spinlock_t *lock,
struct lockdep_map *nest_lock)
{
preempt_disable();
spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
}
EXPORT_SYMBOL(_spin_lock_nest_lock);
#endif
#ifndef _spin_unlock
void __lockfunc _spin_unlock(spinlock_t *lock)
{
__spin_unlock(lock);
}
EXPORT_SYMBOL(_spin_unlock);
#endif
#ifndef _write_unlock
void __lockfunc _write_unlock(rwlock_t *lock)
{
__write_unlock(lock);
}
EXPORT_SYMBOL(_write_unlock);
#endif
#ifndef _read_unlock
void __lockfunc _read_unlock(rwlock_t *lock)
{
__read_unlock(lock);
}
EXPORT_SYMBOL(_read_unlock);
#endif
#ifndef _spin_unlock_irqrestore
void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
{
__spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(_spin_unlock_irqrestore);
#endif
#ifndef _spin_unlock_irq
void __lockfunc _spin_unlock_irq(spinlock_t *lock)
{
__spin_unlock_irq(lock);
}
EXPORT_SYMBOL(_spin_unlock_irq);
#endif
#ifndef _spin_unlock_bh
void __lockfunc _spin_unlock_bh(spinlock_t *lock)
{
__spin_unlock_bh(lock);
}
EXPORT_SYMBOL(_spin_unlock_bh);
#endif
#ifndef _read_unlock_irqrestore
void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
__read_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(_read_unlock_irqrestore);
#endif
#ifndef _read_unlock_irq
void __lockfunc _read_unlock_irq(rwlock_t *lock)
{
__read_unlock_irq(lock);
}
EXPORT_SYMBOL(_read_unlock_irq);
#endif
#ifndef _read_unlock_bh
void __lockfunc _read_unlock_bh(rwlock_t *lock)
{
__read_unlock_bh(lock);
}
EXPORT_SYMBOL(_read_unlock_bh);
#endif
#ifndef _write_unlock_irqrestore
void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
__write_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(_write_unlock_irqrestore);
#endif
#ifndef _write_unlock_irq
void __lockfunc _write_unlock_irq(rwlock_t *lock)
{
__write_unlock_irq(lock);
}
EXPORT_SYMBOL(_write_unlock_irq);
#endif
#ifndef _write_unlock_bh
void __lockfunc _write_unlock_bh(rwlock_t *lock)
{
__write_unlock_bh(lock);
}
EXPORT_SYMBOL(_write_unlock_bh);
#endif
#ifndef _spin_trylock_bh
int __lockfunc _spin_trylock_bh(spinlock_t *lock)
{
return __spin_trylock_bh(lock);
}
EXPORT_SYMBOL(_spin_trylock_bh);
#endif
notrace int in_lock_functions(unsigned long addr)
{
/* Linker adds these: start and end of __lockfunc functions */
extern char __lock_text_start[], __lock_text_end[];
return addr >= (unsigned long)__lock_text_start
&& addr < (unsigned long)__lock_text_end;
}
EXPORT_SYMBOL(in_lock_functions);
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