diff options
| -rw-r--r-- | kernel/spinlock.c | 258 |
1 files changed, 127 insertions, 131 deletions
diff --git a/kernel/spinlock.c b/kernel/spinlock.c index 235a9579a875..41e042219ff6 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -21,6 +21,133 @@ #include <linux/debug_locks.h> #include <linux/module.h> +/* + * 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) +/* + * The __lock_function inlines are taken from + * include/linux/spinlock_api_smp.h + */ +#else +/* + * We build the __lock_function inlines here. They are too large for + * inlining all over the place, but here is only one user per function + * which embedds them into the calling _lock_function below. + * + * 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. + */ +#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; \ +} \ + \ +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; \ +} \ + \ +void __lockfunc __##op##_lock_irq(locktype##_t *lock) \ +{ \ + _##op##_lock_irqsave(lock); \ +} \ + \ +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); \ +} \ + +/* + * 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 + +#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 CONFIG_INLINE_SPIN_TRYLOCK int __lockfunc _spin_trylock(spinlock_t *lock) { @@ -45,13 +172,6 @@ int __lockfunc _write_trylock(rwlock_t *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 CONFIG_INLINE_READ_LOCK void __lockfunc _read_lock(rwlock_t *lock) { @@ -148,130 +268,6 @@ void __lockfunc _write_lock(rwlock_t *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 CONFIG_INLINE_SPIN_UNLOCK void __lockfunc _spin_unlock(spinlock_t *lock) { |