* 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)
*/
-#include <linux/config.h>
#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>
+/*
+ * Generic declaration of the raw read_trylock() function,
+ * architectures are supposed to optimize this:
+ */
+int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock)
+{
+ __raw_read_lock(lock);
+ return 1;
+}
+EXPORT_SYMBOL(generic__raw_read_trylock);
+
int __lockfunc _spin_trylock(spinlock_t *lock)
{
preempt_disable();
- if (_raw_spin_trylock(lock))
+ if (_raw_spin_trylock(lock)) {
+ spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
return 1;
+ }
preempt_enable();
return 0;
}
EXPORT_SYMBOL(_spin_trylock);
-int __lockfunc _write_trylock(rwlock_t *lock)
+int __lockfunc _read_trylock(rwlock_t *lock)
{
preempt_disable();
- if (_raw_write_trylock(lock))
+ if (_raw_read_trylock(lock)) {
+ rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
return 1;
+ }
preempt_enable();
return 0;
}
-EXPORT_SYMBOL(_write_trylock);
-
-#ifdef CONFIG_PREEMPT
-/*
- * This could be a long-held lock. If another CPU holds it for a long time,
- * and that CPU is not asked to reschedule then *this* CPU will spin on the
- * lock for a long time, even if *this* CPU is asked to reschedule.
- *
- * So what we do here, in the slow (contended) path is to spin on the lock by
- * hand while permitting preemption.
- *
- * Called inside preempt_disable().
- */
-static inline void __preempt_spin_lock(spinlock_t *lock)
-{
- if (preempt_count() > 1) {
- _raw_spin_lock(lock);
- return;
- }
-
- do {
- preempt_enable();
- while (spin_is_locked(lock))
- cpu_relax();
- preempt_disable();
- } while (!_raw_spin_trylock(lock));
-}
+EXPORT_SYMBOL(_read_trylock);
-void __lockfunc _spin_lock(spinlock_t *lock)
+int __lockfunc _write_trylock(rwlock_t *lock)
{
preempt_disable();
- if (unlikely(!_raw_spin_trylock(lock)))
- __preempt_spin_lock(lock);
-}
-
-static inline void __preempt_write_lock(rwlock_t *lock)
-{
- if (preempt_count() > 1) {
- _raw_write_lock(lock);
- return;
+ if (_raw_write_trylock(lock)) {
+ rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ return 1;
}
- do {
- preempt_enable();
- while (rwlock_is_locked(lock))
- cpu_relax();
- preempt_disable();
- } while (!_raw_write_trylock(lock));
-}
-
-void __lockfunc _write_lock(rwlock_t *lock)
-{
- preempt_disable();
- if (unlikely(!_raw_write_trylock(lock)))
- __preempt_write_lock(lock);
-}
-#else
-void __lockfunc _spin_lock(spinlock_t *lock)
-{
- preempt_disable();
- _raw_spin_lock(lock);
+ preempt_enable();
+ return 0;
}
+EXPORT_SYMBOL(_write_trylock);
-void __lockfunc _write_lock(rwlock_t *lock)
-{
- preempt_disable();
- _raw_write_lock(lock);
-}
-#endif
-EXPORT_SYMBOL(_spin_lock);
-EXPORT_SYMBOL(_write_lock);
+/*
+ * 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_PREEMPT) || !defined(CONFIG_SMP) || \
+ defined(CONFIG_DEBUG_LOCK_ALLOC)
void __lockfunc _read_lock(rwlock_t *lock)
{
preempt_disable();
+ rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
_raw_read_lock(lock);
}
EXPORT_SYMBOL(_read_lock);
-void __lockfunc _spin_unlock(spinlock_t *lock)
-{
- _raw_spin_unlock(lock);
- preempt_enable();
-}
-EXPORT_SYMBOL(_spin_unlock);
-
-void __lockfunc _write_unlock(rwlock_t *lock)
-{
- _raw_write_unlock(lock);
- preempt_enable();
-}
-EXPORT_SYMBOL(_write_unlock);
-
-void __lockfunc _read_unlock(rwlock_t *lock)
-{
- _raw_read_unlock(lock);
- preempt_enable();
-}
-EXPORT_SYMBOL(_read_unlock);
-
unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
- _raw_spin_lock_flags(lock, flags);
+ spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ /*
+ * On lockdep we dont want the hand-coded irq-enable of
+ * _raw_spin_lock_flags() code, because lockdep assumes
+ * that interrupts are not re-enabled during lock-acquire:
+ */
+#ifdef CONFIG_PROVE_LOCKING
+ _raw_spin_lock(lock);
+#else
+ _raw_spin_lock_flags(lock, &flags);
+#endif
return flags;
}
EXPORT_SYMBOL(_spin_lock_irqsave);
{
local_irq_disable();
preempt_disable();
+ spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
_raw_spin_lock(lock);
}
EXPORT_SYMBOL(_spin_lock_irq);
{
local_bh_disable();
preempt_disable();
+ spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
_raw_spin_lock(lock);
}
EXPORT_SYMBOL(_spin_lock_bh);
local_irq_save(flags);
preempt_disable();
+ rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
_raw_read_lock(lock);
return flags;
}
{
local_irq_disable();
preempt_disable();
+ rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
_raw_read_lock(lock);
}
EXPORT_SYMBOL(_read_lock_irq);
{
local_bh_disable();
preempt_disable();
+ rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
_raw_read_lock(lock);
}
EXPORT_SYMBOL(_read_lock_bh);
local_irq_save(flags);
preempt_disable();
+ rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
_raw_write_lock(lock);
return flags;
}
{
local_irq_disable();
preempt_disable();
+ rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
_raw_write_lock(lock);
}
EXPORT_SYMBOL(_write_lock_irq);
{
local_bh_disable();
preempt_disable();
+ rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
_raw_write_lock(lock);
}
EXPORT_SYMBOL(_write_lock_bh);
+void __lockfunc _spin_lock(spinlock_t *lock)
+{
+ preempt_disable();
+ spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ _raw_spin_lock(lock);
+}
+
+EXPORT_SYMBOL(_spin_lock);
+
+void __lockfunc _write_lock(rwlock_t *lock)
+{
+ preempt_disable();
+ rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ _raw_write_lock(lock);
+}
+
+EXPORT_SYMBOL(_write_lock);
+
+#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) \
+ cpu_relax(); \
+ } \
+ (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) \
+ cpu_relax(); \
+ } \
+ (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_);
+ _raw_spin_lock(lock);
+}
+
+EXPORT_SYMBOL(_spin_lock_nested);
+
+#endif
+
+void __lockfunc _spin_unlock(spinlock_t *lock)
+{
+ spin_release(&lock->dep_map, 1, _RET_IP_);
+ _raw_spin_unlock(lock);
+ preempt_enable();
+}
+EXPORT_SYMBOL(_spin_unlock);
+
+void __lockfunc _write_unlock(rwlock_t *lock)
+{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
+ _raw_write_unlock(lock);
+ preempt_enable();
+}
+EXPORT_SYMBOL(_write_unlock);
+
+void __lockfunc _read_unlock(rwlock_t *lock)
+{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
+ _raw_read_unlock(lock);
+ preempt_enable();
+}
+EXPORT_SYMBOL(_read_unlock);
+
void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
{
+ spin_release(&lock->dep_map, 1, _RET_IP_);
_raw_spin_unlock(lock);
local_irq_restore(flags);
preempt_enable();
void __lockfunc _spin_unlock_irq(spinlock_t *lock)
{
+ spin_release(&lock->dep_map, 1, _RET_IP_);
_raw_spin_unlock(lock);
local_irq_enable();
preempt_enable();
void __lockfunc _spin_unlock_bh(spinlock_t *lock)
{
+ spin_release(&lock->dep_map, 1, _RET_IP_);
_raw_spin_unlock(lock);
- preempt_enable();
- local_bh_enable();
+ preempt_enable_no_resched();
+ local_bh_enable_ip((unsigned long)__builtin_return_address(0));
}
EXPORT_SYMBOL(_spin_unlock_bh);
void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
_raw_read_unlock(lock);
local_irq_restore(flags);
preempt_enable();
void __lockfunc _read_unlock_irq(rwlock_t *lock)
{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
_raw_read_unlock(lock);
local_irq_enable();
preempt_enable();
void __lockfunc _read_unlock_bh(rwlock_t *lock)
{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
_raw_read_unlock(lock);
- preempt_enable();
- local_bh_enable();
+ preempt_enable_no_resched();
+ local_bh_enable_ip((unsigned long)__builtin_return_address(0));
}
EXPORT_SYMBOL(_read_unlock_bh);
void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
_raw_write_unlock(lock);
local_irq_restore(flags);
preempt_enable();
void __lockfunc _write_unlock_irq(rwlock_t *lock)
{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
_raw_write_unlock(lock);
local_irq_enable();
preempt_enable();
void __lockfunc _write_unlock_bh(rwlock_t *lock)
{
+ rwlock_release(&lock->dep_map, 1, _RET_IP_);
_raw_write_unlock(lock);
- preempt_enable();
- local_bh_enable();
+ preempt_enable_no_resched();
+ local_bh_enable_ip((unsigned long)__builtin_return_address(0));
}
EXPORT_SYMBOL(_write_unlock_bh);
{
local_bh_disable();
preempt_disable();
- if (_raw_spin_trylock(lock))
+ if (_raw_spin_trylock(lock)) {
+ spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
return 1;
+ }
- preempt_enable();
- local_bh_enable();
+ preempt_enable_no_resched();
+ local_bh_enable_ip((unsigned long)__builtin_return_address(0));
return 0;
}
EXPORT_SYMBOL(_spin_trylock_bh);