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a5ef7ca0e2
Architectures other than mips and x86 are not using ticket spinlocks. Therefore, the contention on the lock is meaningless, since there is nobody known to be waiting on it (arguably /fairly/ unfair locks). Dummy it out to return 0 on other architectures. Signed-off-by: Kyle McMartin <kyle@redhat.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
373 lines
11 KiB
C
373 lines
11 KiB
C
#ifndef __LINUX_SPINLOCK_H
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#define __LINUX_SPINLOCK_H
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/*
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* include/linux/spinlock.h - generic spinlock/rwlock declarations
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*
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* here's the role of the various spinlock/rwlock related include files:
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*
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* on SMP builds:
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*
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* asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
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* initializers
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*
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* linux/spinlock_types.h:
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* defines the generic type and initializers
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*
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* asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel
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* implementations, mostly inline assembly code
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*
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* (also included on UP-debug builds:)
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*
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* linux/spinlock_api_smp.h:
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* contains the prototypes for the _spin_*() APIs.
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*
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* linux/spinlock.h: builds the final spin_*() APIs.
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*
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* on UP builds:
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*
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* linux/spinlock_type_up.h:
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* contains the generic, simplified UP spinlock type.
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* (which is an empty structure on non-debug builds)
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*
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* linux/spinlock_types.h:
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* defines the generic type and initializers
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*
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* linux/spinlock_up.h:
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* contains the __raw_spin_*()/etc. version of UP
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* builds. (which are NOPs on non-debug, non-preempt
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* builds)
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*
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* (included on UP-non-debug builds:)
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*
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* linux/spinlock_api_up.h:
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* builds the _spin_*() APIs.
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*
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* linux/spinlock.h: builds the final spin_*() APIs.
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*/
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#include <linux/typecheck.h>
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#include <linux/preempt.h>
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#include <linux/linkage.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <linux/kernel.h>
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#include <linux/stringify.h>
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#include <linux/bottom_half.h>
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#include <asm/system.h>
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/*
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* Must define these before including other files, inline functions need them
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*/
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#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
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#define LOCK_SECTION_START(extra) \
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".subsection 1\n\t" \
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extra \
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".ifndef " LOCK_SECTION_NAME "\n\t" \
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LOCK_SECTION_NAME ":\n\t" \
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".endif\n"
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#define LOCK_SECTION_END \
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".previous\n\t"
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#define __lockfunc __attribute__((section(".spinlock.text")))
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/*
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* Pull the raw_spinlock_t and raw_rwlock_t definitions:
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*/
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#include <linux/spinlock_types.h>
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extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
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/*
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* Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
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*/
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#ifdef CONFIG_SMP
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# include <asm/spinlock.h>
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#else
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# include <linux/spinlock_up.h>
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#endif
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#ifdef CONFIG_DEBUG_SPINLOCK
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extern void __spin_lock_init(spinlock_t *lock, const char *name,
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struct lock_class_key *key);
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# define spin_lock_init(lock) \
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do { \
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static struct lock_class_key __key; \
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\
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__spin_lock_init((lock), #lock, &__key); \
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} while (0)
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#else
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# define spin_lock_init(lock) \
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do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
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#endif
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#ifdef CONFIG_DEBUG_SPINLOCK
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extern void __rwlock_init(rwlock_t *lock, const char *name,
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struct lock_class_key *key);
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# define rwlock_init(lock) \
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do { \
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static struct lock_class_key __key; \
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\
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__rwlock_init((lock), #lock, &__key); \
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} while (0)
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#else
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# define rwlock_init(lock) \
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do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
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#endif
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#define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock)
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#ifdef CONFIG_GENERIC_LOCKBREAK
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#define spin_is_contended(lock) ((lock)->break_lock)
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#else
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#ifdef __raw_spin_is_contended
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#define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
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#else
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#define spin_is_contended(lock) (((void)(lock), 0))
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#endif /*__raw_spin_is_contended*/
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#endif
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/**
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* spin_unlock_wait - wait until the spinlock gets unlocked
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* @lock: the spinlock in question.
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*/
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#define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock)
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/*
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* Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
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*/
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#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
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# include <linux/spinlock_api_smp.h>
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#else
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# include <linux/spinlock_api_up.h>
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#endif
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#ifdef CONFIG_DEBUG_SPINLOCK
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extern void _raw_spin_lock(spinlock_t *lock);
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#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
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extern int _raw_spin_trylock(spinlock_t *lock);
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extern void _raw_spin_unlock(spinlock_t *lock);
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extern void _raw_read_lock(rwlock_t *lock);
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extern int _raw_read_trylock(rwlock_t *lock);
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extern void _raw_read_unlock(rwlock_t *lock);
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extern void _raw_write_lock(rwlock_t *lock);
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extern int _raw_write_trylock(rwlock_t *lock);
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extern void _raw_write_unlock(rwlock_t *lock);
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#else
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# define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock)
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# define _raw_spin_lock_flags(lock, flags) \
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__raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
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# define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock)
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# define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock)
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# define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock)
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# define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock)
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# define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock)
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# define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock)
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# define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock)
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# define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock)
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#endif
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#define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock)
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#define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock)
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/*
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* Define the various spin_lock and rw_lock methods. Note we define these
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* regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
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* methods are defined as nops in the case they are not required.
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*/
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#define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock))
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#define read_trylock(lock) __cond_lock(lock, _read_trylock(lock))
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#define write_trylock(lock) __cond_lock(lock, _write_trylock(lock))
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#define spin_lock(lock) _spin_lock(lock)
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
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# define spin_lock_nest_lock(lock, nest_lock) \
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do { \
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typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
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_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
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} while (0)
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#else
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# define spin_lock_nested(lock, subclass) _spin_lock(lock)
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# define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
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#endif
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#define write_lock(lock) _write_lock(lock)
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#define read_lock(lock) _read_lock(lock)
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#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
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#define spin_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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flags = _spin_lock_irqsave(lock); \
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} while (0)
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#define read_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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flags = _read_lock_irqsave(lock); \
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} while (0)
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#define write_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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flags = _write_lock_irqsave(lock); \
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} while (0)
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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#define spin_lock_irqsave_nested(lock, flags, subclass) \
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do { \
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typecheck(unsigned long, flags); \
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flags = _spin_lock_irqsave_nested(lock, subclass); \
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} while (0)
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#else
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#define spin_lock_irqsave_nested(lock, flags, subclass) \
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do { \
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typecheck(unsigned long, flags); \
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flags = _spin_lock_irqsave(lock); \
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} while (0)
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#endif
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#else
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#define spin_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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_spin_lock_irqsave(lock, flags); \
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} while (0)
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#define read_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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_read_lock_irqsave(lock, flags); \
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} while (0)
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#define write_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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_write_lock_irqsave(lock, flags); \
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} while (0)
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#define spin_lock_irqsave_nested(lock, flags, subclass) \
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spin_lock_irqsave(lock, flags)
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#endif
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#define spin_lock_irq(lock) _spin_lock_irq(lock)
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#define spin_lock_bh(lock) _spin_lock_bh(lock)
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#define read_lock_irq(lock) _read_lock_irq(lock)
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#define read_lock_bh(lock) _read_lock_bh(lock)
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#define write_lock_irq(lock) _write_lock_irq(lock)
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#define write_lock_bh(lock) _write_lock_bh(lock)
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/*
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* We inline the unlock functions in the nondebug case:
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*/
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#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
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!defined(CONFIG_SMP)
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# define spin_unlock(lock) _spin_unlock(lock)
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# define read_unlock(lock) _read_unlock(lock)
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# define write_unlock(lock) _write_unlock(lock)
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# define spin_unlock_irq(lock) _spin_unlock_irq(lock)
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# define read_unlock_irq(lock) _read_unlock_irq(lock)
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# define write_unlock_irq(lock) _write_unlock_irq(lock)
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#else
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# define spin_unlock(lock) \
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do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
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# define read_unlock(lock) \
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do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
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# define write_unlock(lock) \
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do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
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# define spin_unlock_irq(lock) \
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do { \
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__raw_spin_unlock(&(lock)->raw_lock); \
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__release(lock); \
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local_irq_enable(); \
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} while (0)
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# define read_unlock_irq(lock) \
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do { \
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__raw_read_unlock(&(lock)->raw_lock); \
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__release(lock); \
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local_irq_enable(); \
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} while (0)
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# define write_unlock_irq(lock) \
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do { \
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__raw_write_unlock(&(lock)->raw_lock); \
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__release(lock); \
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local_irq_enable(); \
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} while (0)
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#endif
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#define spin_unlock_irqrestore(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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_spin_unlock_irqrestore(lock, flags); \
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} while (0)
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#define spin_unlock_bh(lock) _spin_unlock_bh(lock)
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#define read_unlock_irqrestore(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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_read_unlock_irqrestore(lock, flags); \
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} while (0)
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#define read_unlock_bh(lock) _read_unlock_bh(lock)
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#define write_unlock_irqrestore(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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_write_unlock_irqrestore(lock, flags); \
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} while (0)
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#define write_unlock_bh(lock) _write_unlock_bh(lock)
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#define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock))
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#define spin_trylock_irq(lock) \
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({ \
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local_irq_disable(); \
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spin_trylock(lock) ? \
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1 : ({ local_irq_enable(); 0; }); \
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})
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#define spin_trylock_irqsave(lock, flags) \
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({ \
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local_irq_save(flags); \
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spin_trylock(lock) ? \
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1 : ({ local_irq_restore(flags); 0; }); \
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})
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#define write_trylock_irqsave(lock, flags) \
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({ \
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local_irq_save(flags); \
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write_trylock(lock) ? \
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1 : ({ local_irq_restore(flags); 0; }); \
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})
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/*
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* Pull the atomic_t declaration:
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* (asm-mips/atomic.h needs above definitions)
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*/
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#include <asm/atomic.h>
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/**
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* atomic_dec_and_lock - lock on reaching reference count zero
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* @atomic: the atomic counter
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* @lock: the spinlock in question
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*
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* Decrements @atomic by 1. If the result is 0, returns true and locks
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* @lock. Returns false for all other cases.
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*/
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extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
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#define atomic_dec_and_lock(atomic, lock) \
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__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
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/**
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* spin_can_lock - would spin_trylock() succeed?
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* @lock: the spinlock in question.
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*/
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#define spin_can_lock(lock) (!spin_is_locked(lock))
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#endif /* __LINUX_SPINLOCK_H */
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