3b4beb3175
Used to contain the address of the holder of the lock. But since the spinlock code is not inlined anymore all locks contain the same address anyway. And since in addtition nobody complained about that for ages its obviously unused. So remove it. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
167 lines
4 KiB
C
167 lines
4 KiB
C
/*
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* include/asm-s390/spinlock.h
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*
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* Derived from "include/asm-i386/spinlock.h"
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*/
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#ifndef __ASM_SPINLOCK_H
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#define __ASM_SPINLOCK_H
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#include <linux/smp.h>
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#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
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static inline int
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_raw_compare_and_swap(volatile unsigned int *lock,
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unsigned int old, unsigned int new)
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{
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asm volatile(
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" cs %0,%3,%1"
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: "=d" (old), "=Q" (*lock)
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: "0" (old), "d" (new), "Q" (*lock)
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: "cc", "memory" );
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return old;
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}
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#else /* __GNUC__ */
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static inline int
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_raw_compare_and_swap(volatile unsigned int *lock,
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unsigned int old, unsigned int new)
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{
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asm volatile(
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" cs %0,%3,0(%4)"
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: "=d" (old), "=m" (*lock)
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: "0" (old), "d" (new), "a" (lock), "m" (*lock)
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: "cc", "memory" );
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return old;
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}
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#endif /* __GNUC__ */
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/*
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* Simple spin lock operations. There are two variants, one clears IRQ's
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* on the local processor, one does not.
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*
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* We make no fairness assumptions. They have a cost.
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*
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* (the type definitions are in asm/spinlock_types.h)
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*/
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#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)
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#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
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#define __raw_spin_unlock_wait(lock) \
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do { while (__raw_spin_is_locked(lock)) \
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_raw_spin_relax(lock); } while (0)
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extern void _raw_spin_lock_wait(raw_spinlock_t *);
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extern int _raw_spin_trylock_retry(raw_spinlock_t *);
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extern void _raw_spin_relax(raw_spinlock_t *lock);
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static inline void __raw_spin_lock(raw_spinlock_t *lp)
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{
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int old;
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old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
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if (likely(old == 0))
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return;
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_raw_spin_lock_wait(lp);
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}
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static inline int __raw_spin_trylock(raw_spinlock_t *lp)
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{
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int old;
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old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
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if (likely(old == 0))
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return 1;
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return _raw_spin_trylock_retry(lp);
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}
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static inline void __raw_spin_unlock(raw_spinlock_t *lp)
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{
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_raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);
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}
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/*
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* Read-write spinlocks, allowing multiple readers
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* but only one writer.
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*
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* NOTE! it is quite common to have readers in interrupts
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* but no interrupt writers. For those circumstances we
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* can "mix" irq-safe locks - any writer needs to get a
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* irq-safe write-lock, but readers can get non-irqsafe
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* read-locks.
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*/
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/**
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* read_can_lock - would read_trylock() succeed?
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* @lock: the rwlock in question.
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*/
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#define __raw_read_can_lock(x) ((int)(x)->lock >= 0)
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/**
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* write_can_lock - would write_trylock() succeed?
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* @lock: the rwlock in question.
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*/
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#define __raw_write_can_lock(x) ((x)->lock == 0)
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extern void _raw_read_lock_wait(raw_rwlock_t *lp);
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extern int _raw_read_trylock_retry(raw_rwlock_t *lp);
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extern void _raw_write_lock_wait(raw_rwlock_t *lp);
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extern int _raw_write_trylock_retry(raw_rwlock_t *lp);
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static inline void __raw_read_lock(raw_rwlock_t *rw)
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{
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unsigned int old;
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old = rw->lock & 0x7fffffffU;
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if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)
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_raw_read_lock_wait(rw);
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}
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static inline void __raw_read_unlock(raw_rwlock_t *rw)
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{
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unsigned int old, cmp;
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old = rw->lock;
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do {
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cmp = old;
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old = _raw_compare_and_swap(&rw->lock, old, old - 1);
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} while (cmp != old);
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}
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static inline void __raw_write_lock(raw_rwlock_t *rw)
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{
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if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
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_raw_write_lock_wait(rw);
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}
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static inline void __raw_write_unlock(raw_rwlock_t *rw)
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{
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_raw_compare_and_swap(&rw->lock, 0x80000000, 0);
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}
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static inline int __raw_read_trylock(raw_rwlock_t *rw)
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{
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unsigned int old;
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old = rw->lock & 0x7fffffffU;
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if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old))
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return 1;
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return _raw_read_trylock_retry(rw);
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}
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static inline int __raw_write_trylock(raw_rwlock_t *rw)
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{
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if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
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return 1;
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return _raw_write_trylock_retry(rw);
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}
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#define _raw_read_relax(lock) cpu_relax()
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#define _raw_write_relax(lock) cpu_relax()
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#endif /* __ASM_SPINLOCK_H */
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